BLEClient Component

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An easy-to-use Bluetooth Low Energy (BLE) GATT Client component.

Syntax

TiplBLEClient

Remarks

The BLEClient component provides a simple but flexible BLE GATT client implementation, making it easy to work with the services, characteristics, and descriptors exposed by BLE GATT servers on remote devices.

Prerequisites

Important: Please note that the BLEClient component is only supported by Windows 10 Creator's Update (10.0.15063.0) and later.

Scanning and Connecting

To begin, call the StartScanning method, optionally passing in a list of service UUIDs that you're interested in so that irrelevant devices are ignored during scanning. While the component is scanning, the Advertisement event will fire for each relevant advertisement received from a GATT server.

The Advertisement event provides a wealth of information about the remote device, such as its Id and local name, whether or not you can connect to it, the list of service UUIDs it's advertising, and much more.

Once you've determined what device you wish to connect to, call the Connect method and pass its server Id, obtained from the Advertisement event. The component will stop scanning, then attempt to connect to the device. The Connected event is fired when the connection attempt finishes, and will contain error information in case of a failure.

// StartScan, StopScan, and Advertisement event handlers. bleclient1.OnStartScan += (s, e) => Console.WriteLine("Scanning has started"); bleclient1.OnStopScan += (s, e) => Console.WriteLine("Scanning has stopped"); bleclient1.OnAdvertisement += (s, e) => { // Your application should make every effort to handle the Advertisement event quickly. // BLEClient fires it as often as necessary, often multiple times per second. Console.WriteLine("Advertisement Received:\r\n\tServerId: " + e.ServerId + "\r\n\tName: " + e.Name + "\r\n\tServiceUuids: " + e.ServiceUuids + "\r\n\tManufacturerCompanyId: " + e.ManufacturerCompanyId + "\r\n\tIsConnectable: " + e.IsConnectable); }; // Scan for all devices. bleclient1.StartScanning(""); // Alternatively, you can scan for devices advertising specific service UUIDs. You can use a // mixture of 16-, 32-, and 128-bit UUID strings, they'll be converted to 128-bit internally. bleclient1.StartScanning("180A,0000180F,00001801-0000-1000-8000-00805F9B34FB"); // ...Once you find a device you wish to connect to... bleclient1.Connect("SERVER_ID");

Refer the StartScanning for more detailed code examples.

Service, Characteristic, and Descriptor Discovery

Once connected to a device, the next step is to discover the services that you're interested in. To do this, call the DiscoverServices method, optionally passing a list of service UUIDs to limit the discovery process. For each service discovered, ServiceCount will be incremented, and the Discovered event will fire.

After you've discovered the services you're interested in, you have to discover those services' characteristics. This is done with the DiscoverCharacteristics method, passing the Id of the service you wish to discover characteristics for, and optionally passing a list of characteristic UUIDs to limit the discovery process. For each characteristic discovered, CharacteristicCount will be incremented, and the Discovered event will fire.

Finally, you can discover descriptors for the discovered characteristics. To do this, you use the DiscoverDescriptors method, passing the Id of a characteristic, as well as the Id of the service which owns it. For each descriptor discovered, DescriptorCount will be incremented, and the Discovered event will fire.

If you would prefer to do multiple discovery steps with a single call, you can use the Discover method rather than the individual DiscoverServices, DiscoverCharacteristics, and DiscoverDescriptors methods. However, keep in mind that doing so will consume more power up front. Discovering services, characteristics, and descriptors as you need them is more energy-efficient.

// Discovered event handler. bleclient1.OnDiscovered += (s, e) => { string gattType = e.GattType == 0 ? "Service" : (e.GattType == 1 ? "Characteristic" : "Descriptor"); Console.WriteLine(gattType + " discovered:" + // The 128-bit UUID string, "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX". "\r\n\tUUID: " + e.Uuid + // For standard GATT objects whose UUIDs are defined by the Bluetooth // SIG, the Description event parameter will contain their name. "\r\n\tDescription: " + e.Description); }; string serviceIds = "180A,F000AA70-0451-4000-B000-000000000000,F000AA20-0451-4000-B000-000000000000"; // Discover specific root services. bleclient1.DiscoverServices(serviceIds, ""); foreach (Service s in bleclient1.Services) { // Discover all characteristics for this service. bleclient1.DiscoverCharacteristics(s.Id, ""); bleclient1.Service = s.Id; foreach (Characteristic c in bleclient1) { // Discover all descriptors for this characteristic. bleclient1.DiscoverDescriptors(s.Id, c.Id); } }

Refer to DiscoverServices, DiscoverCharacteristics, DiscoverDescriptors, and Discover for more detailed code examples.

Working with Discovered Data

Once you've discovered the services, characteristics, and descriptors that you need, you'll want to make use of them. BLEClient makes it easy to navigate the GATT data hierarchy. Start by iterating over the objects in the Services collection and inspecting the information discovered for each service.

Set the Service property to a specific service's Id to have the component populate the Characteristics collection based on the characteristics discovered for that service. You can then iterate over the characteristic objects to inspect the details of each characteristic. Depending on what flags a characteristic has, you may also be able to directly manipulate some of its information.

Set the Characteristic property to a specific characteristic's Id to have the component populate the Descriptors collection based on the descriptors discovered for that characteristic. You can then iterate over the descriptor objects to inspect the details of each descriptor.

// Loop through all discovered GATT objects and print out their UUIDs and descriptions. foreach (Service s in bleclient1.Services) { Console.WriteLine("Service: " + s.Description + " (" + s.Uuid + ")"); // Select this service and loop through its characteristics. bleclient1.Service = s.Id; foreach (Characteristic c in bleclient1.Characteristics) { Console.WriteLine("\tCharacteristic: " + c.Description + " (" + c.Uuid + ")"); // Select this characteristic and loop through its descriptors. bleclient1.Characteristic = c.Id; foreach (Descriptor d in bleclient1.Descriptors) { Console.WriteLine("\t\tDescriptor: " + d.Description + " (" + d.Uuid + ")"); } } }

Reading and Writing Values

The BLEClient component exposes CharacteristicCachedValue and DescriptorCachedValue properties, which retrieve values from the local system's value cache, preventing unnecessary power drain involved with communicating with the device.

// Print the cached value for a characteristic (which you can assume // we've already found and assigned to a variable called "c"). Console.WriteLine("Characteristic Value: " + BitConverter.ToUInt16(c.CachedValueB, 0)); // Print the cached value for a descriptor (again, assume it's stored in "d"). Console.WriteLine("Descriptor Value: " + BitConverter.ToString(d.CachedValueB));

To read a value directly from the remote device's GATT server, use the ReadValue method. For characteristics, you'll need to pass the Ids of the characteristic and the service which owns it. For descriptors, you'll pass both of those, as well as the Id of the descriptor. If the read succeeds, the method will return the value read from the device, and the Value event will be fired. If the read fails, the Error event is fired and the component raises an exception.

// Value event handler. bleclient1.OnValue += (s, e) => { Console.WriteLine("Read value {" + BitConverter.ToString(e.ValueB) + "} for " + (string.IsNullOrEmpty(e.DescriptorId) ? "characteristic" : "descriptor") + " with UUID " + e.Uuid); }; // Prints the live value for a characteristic. bleclient1.ReadValue("001C00000000", "001C001D0000", ""); // Prints the live value for a descriptor. bleclient1.ReadValue("001C00000000", "001C001D0000", "001C001D0021");

To write a characteristic or descriptor value, call the WriteValue method, passing the appropriate Ids and the value to be written. If the write succeeds, the method will return and the WriteResponse event will fire. If the write fails, the Error event is fired and the component raises an exception.

// WriteResponse event handler. bleclient1.OnWriteResponse += (s, e) => { string gattType = string.IsNullOrEmpty(e.DescriptorId) ? "characteristic" : "descriptor"; Console.WriteLine("Successfully wrote to " + gattType + " with UUID " + e.Uuid); }; // Write to a characteristic. bleclient1.WriteValue("004200000000", "004200460000", "", new byte[] { 0x1 }); // Write to a descriptor. bleclient1.WriteValue("004200000000", "004200430000", "004200430045", new byte[] { 0x1 });

You can also use the PostValue method to write values to characteristics that have the "Write Without Response" flag. Posting a value to a characteristic is more energy-efficient since the remote device's GATT server won't send back an acknowledgement, even if the write fails.

// Write without response to a characteristic. bleclient1.PostValue("00AA00000000", "00AA00BB0000", new byte[] { 0x1, 0x2, 0x3 });

Keep in mind that not all characteristics and descriptors support value writes, and some might not even support value reads. If you attempt to perform an operation that a characteristic or descriptor doesn't support, the component raises an exception.

For characteristics, you can inspect the CharacteristicFlags property to determine what operations the characteristic supports. For descriptors, you'll either need to know in advance what operations are supported, or be ready to handle exceptions which may occur.

Refer to ReadValue, WriteValue, and PostValue for more detailed code examples.

Subscribing to Characteristics

One of the most important features of the BLE GATT data model is the ability for a GATT server to send characteristic value updates to interested GATT clients in real-time. A GATT client can subscribe to either notifications or indications to get value updates. The difference between the two is simple: notifications are not acknowledged by GATT clients, while indications are.

When you want to subscribe to a characteristic, start by checking the CharacteristicCanSubscribe property to determine if it supports subscriptions.

For characteristics which do support subscriptions, you can subscribe and unsubscribe by using either the CharacteristicSubscribed property or the Subscribe and Unsubscribe methods. The Subscribed and Unsubscribed events are fired whenever a characteristic's subscription state changes, and the Value event is fired whenever a value update is received.

Note that characteristics do not have to support both subscription types, or even one of them. For characteristics which do support both, the component will subscribe for notifications by default. If you'd prefer that it subscribe for indications instead, enable the PreferIndications configuration setting.

// Subscribed, Unsubscribed, and Value event handlers. bleclient1.OnSubscribed += (s, e) => { Console.WriteLine("Subscribed to characteristic:" + "\r\n\tID: " + e.CharacteristicId + "\r\n\tUUID: " + e.Uuid + "\r\n\tDescription: " + e.Description); }; bleclient1.OnUnsubscribed += (s, e) => { Console.WriteLine("Unsubscribed from characteristic:" + "\r\n\tID: " + e.CharacteristicId + "\r\n\tUUID: " + e.Uuid + "\r\n\tDescription: " + e.Description); }; bleclient1.OnValue += (s, e) => { Console.WriteLine("Value update received for characteristic: " + "\r\n\tID: " + e.CharacteristicId + "\r\n\tUUID: " + e.Uuid + "\r\n\tDescription: " + e.Description + "\r\n\tValue: " + BitConverter.ToString(e.ValueB)); }; // Assume that we've already found a characteristic, its owning service, // and a descriptor on it; and we've stored them in variables called "c", // "s", and "d", respectively. You can subscribe to and unsubscribe from // the characteristic using any, or all, of the three methods below. // Subscribe and unsubscribe using methods. bleclient1.Subscribe(s.Id, c.Id); // ... bleclient1.Unsubscribe(s.Id, c.Id); // Subscribe and unsubscribe using the "Subscribed" field. c.Subscribed = true; // ... c.Subscribed = false; // Subscribe and unsubscribe by writing directly to the CCCD. bleclient1.WriteValue(s.Id, c.Id, d.Id, new byte[] { 1, 0 }); // ... bleclient1.WriteValue(s.Id, c.Id, d.Id, new byte[] { 0, 0 });

Usage Notes

It is very important that you do not block or perform any long-running operations within the component's event handlers. The platform APIs that the component uses rely on timely delivery of events in order to function properly.

Most platforms will in some way limit the use of Bluetooth APIs when your application is in the background. Be aware of the limitations your platform places on the usage of BLE APIs while in the background, and be ready to act accordingly.

Be sure to disconnect from a remote device by calling Disconnect when you're finished using it. When you're completely finished using the BLEClient component, be sure that you've called StopScanning and Disconnect before disposing of the instance.

Property List

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The following is the full list of the properties of the component with short descriptions. Click on the links for further details.

Method List

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The following is the full list of the methods of the component with short descriptions. Click on the links for further details.

Event List

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The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.

Config Settings

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The following is a list of config settings for the component with short descriptions. Click on the links for further details.

ActiveScanning Property (BLEClient Component)

Whether to use active scanning.

Syntax

__property bool ActiveScanning = { read=FActiveScanning, write=FSetActiveScanning };

Default Value

false

Remarks

When enabled, the component will instruct the system to use active scanning rather than passive scanning, at the cost of higher power consumption.

Active scanning causes the system's BLE API to request a scan response packet for each advertisement received, which in turn means that you will be able to get more information from devices without connecting to them.

The tradeoff is that enabling this feature increases power consumption for both the client and server, but if your use-case doesn't call for ever actually connecting to the devices (which itself can be a power-intensive operation), then that tradeoff might be mitigated.

Note that you cannot change the value of the ActiveScanning property if the component is already scanning.

Active Scanning // Enable active scanning. bleclient1.ActiveScanning = true; bleclient1.StartScanning(""); // ... bleclient1.StopScanning();

This property is not available at design time.

Data Type

Boolean

Characteristic Property (BLEClient Component)

The currently selected characteristic's Id.

Syntax

__property String Characteristic = { read=FCharacteristic, write=FSetCharacteristic };

Default Value

""

Remarks

Setting the Characteristic property to the Id of a discovered characteristic allows you to inspect the descriptors which have been discovered for it using the Descriptors collection.

Characteristic can either be set to the Id of a characteristic which has been discovered for the service currently selected by Service, or to empty string.

This property is automatically set when you call the Select method; and it is reset to empty string when you set Service.

This property is not available at design time.

Data Type

String

CharacteristicCount Property (BLEClient Component)

The number of records in the Characteristic arrays.

Syntax

__property int CharacteristicCount = { read=FCharacteristicCount, write=FSetCharacteristicCount };

Default Value

0

Remarks

This property controls the size of the following arrays:

• CharacteristicCanSubscribe
• CharacteristicDescription
• CharacteristicFlags
• CharacteristicId
• CharacteristicUserDescription
• CharacteristicUuid
• CharacteristicValueExponent
• CharacteristicValueFormat
• CharacteristicValueFormatCount
• CharacteristicValueFormatIndex
• CharacteristicValueUnit

The array indices start at 0 and end at CharacteristicCount - 1.

This property is not available at design time.

Data Type

Integer

CharacteristicCanSubscribe Property (BLEClient Component)

Whether or not you can subscribe to receive value updates for this characteristic.

Syntax

__property bool CharacteristicCanSubscribe[int CharacteristicIndex] = { read=FCharacteristicCanSubscribe };

Default Value

false

Remarks

Whether or not you can subscribe to receive value updates for this characteristic.

The CharacteristicIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CharacteristicCount property.

This property is read-only and not available at design time.

Data Type

Boolean

CharacteristicDescription Property (BLEClient Component)

This characteristic's Bluetooth SIG user-friendly name, if one is defined.

Syntax

__property String CharacteristicDescription[int CharacteristicIndex] = { read=FCharacteristicDescription };

Default Value

""

Remarks

This characteristic's Bluetooth SIG user-friendly name, if one is defined.

The CharacteristicIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CharacteristicCount property.

This property is read-only and not available at design time.

Data Type

String

CharacteristicFlags Property (BLEClient Component)

A bitmask of this characteristic's flags.

Syntax

__property int CharacteristicFlags[int CharacteristicIndex] = { read=FCharacteristicFlags };

Default Value

0

Remarks

A bitmask of this characteristic's flags.

This property is a bitmask which represents all of the flags (or, in BLE terms, "properties") which this characteristic has set. The following table shows what bitmask is used to represent each flag:

Note that, on some platforms, the component might have to automatically discover specific descriptors for the value this returns to be accurate. The component take care of handling this automatic discovery in the most energy-efficient manner possible.

The CharacteristicIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CharacteristicCount property.

This property is read-only and not available at design time.

Data Type

Integer

CharacteristicId Property (BLEClient Component)

An identification string which uniquely identifies this instance of this characteristic.

Syntax

__property String CharacteristicId[int CharacteristicIndex] = { read=FCharacteristicId };

Default Value

""

Remarks

An identification string which uniquely identifies this instance of this characteristic.

This identification string is guaranteed to be unchanged while the component remains connected to the device.

The CharacteristicIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CharacteristicCount property.

This property is read-only and not available at design time.

Data Type

String

CharacteristicUserDescription Property (BLEClient Component)

The value of the user description descriptor for this characteristic.

Syntax

__property String CharacteristicUserDescription[int CharacteristicIndex] = { read=FCharacteristicUserDescription, write=FSetCharacteristicUserDescription };

Default Value

""

Remarks

The value of the user description descriptor for this characteristic.

If the "Writable Auxiliaries" property is set for this characteristic, you can change this value, which updates it on the server too.

Note that, on some platforms, the component might have to automatically discover specific descriptors for the value this returns to be accurate. The component take care of handling this automatic discovery in the most energy-efficient manner possible.

The CharacteristicIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CharacteristicCount property.

This property is not available at design time.

Data Type

String

CharacteristicUuid Property (BLEClient Component)

This characteristic's 128-bit UUID string.

Syntax

__property String CharacteristicUuid[int CharacteristicIndex] = { read=FCharacteristicUuid };

Default Value

""

Remarks

This characteristic's 128-bit UUID string.

The CharacteristicIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CharacteristicCount property.

This property is read-only and not available at design time.

Data Type

String

CharacteristicValueExponent Property (BLEClient Component)

The exponent of this characteristic's value, for applicable value formats.

Syntax

__property int CharacteristicValueExponent[int CharacteristicIndex] = { read=FCharacteristicValueExponent };

Default Value

-1

Remarks

The exponent of this characteristic's value, for applicable value formats.

For an applicable CharacteristicValueFormat, this signed integer should be used as an exponent in the following formula in order to determine the actual value of the characteristic: [Value] * 10^[Exponent].

The CharacteristicIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CharacteristicCount property.

This property is read-only and not available at design time.

Data Type

Integer

CharacteristicValueFormat Property (BLEClient Component)

The data type of this characteristic's value.

Syntax

__property TiplBLEClientCharacteristicValueFormats CharacteristicValueFormat[int CharacteristicIndex] = { read=FCharacteristicValueFormat };

enum TiplBLEClientCharacteristicValueFormats {
  vfUndefined=0,
  vfBoolean=1,
  vf2Bit=2,
  vfNibble=3,
  vfUInt8=4,
  vfUInt12=5,
  vfUInt16=6,
  vfUInt24=7,
  vfUInt32=8,
  vfUInt48=9,
  vfUInt64=10,
  vfUInt128=11,
  vfSInt8=12,
  vfSInt12=13,
  vfSInt16=14,
  vfSInt24=15,
  vfSInt32=16,
  vfSInt48=17,
  vfSInt64=18,
  vfSInt128=19,
  vfFloat32=20,
  vfFloat64=21,
  vfSFloat=22,
  vfFloat=23,
  vfDUInt16=24,
  vfUtf8Str=25,
  vfUtf16Str=26,
  vfStruct=27
};

Default Value

vfUndefined

Remarks

The data type of this characteristic's value.

The valid options are as follows:

The CharacteristicIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CharacteristicCount property.

This property is read-only and not available at design time.

Data Type

Integer

CharacteristicValueFormatCount Property (BLEClient Component)

The number of value formats this characteristic has.

Syntax

__property int CharacteristicValueFormatCount[int CharacteristicIndex] = { read=FCharacteristicValueFormatCount };

Default Value

0

Remarks

The number of value formats this characteristic has.

Characteristics whose values are an aggregate of multiple other values will often have multiple value formats as a result. In such cases, this property's value will be greater than 1, and the CharacteristicValueFormatIndex property can be used to choose which value format the CharacteristicValueFormat, CharacteristicValueExponent, and CharacteristicValueUnit properties are populated with.

Note that, on some platforms, the component might have to automatically discover specific descriptors for the value this returns to be accurate. The component take care of handling this automatic discovery in the most energy-efficient manner possible.

The CharacteristicIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CharacteristicCount property.

This property is read-only and not available at design time.

Data Type

Integer

CharacteristicValueFormatIndex Property (BLEClient Component)

Selects the currently populated value format details for this characteristic.

Syntax

__property int CharacteristicValueFormatIndex[int CharacteristicIndex] = { read=FCharacteristicValueFormatIndex, write=FSetCharacteristicValueFormatIndex };

Default Value

-1

Remarks

Selects the currently populated value format details for this characteristic.

See CharacteristicValueFormatCount for more details.

The CharacteristicIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CharacteristicCount property.

This property is not available at design time.

Data Type

Integer

CharacteristicValueUnit Property (BLEClient Component)

The 128-bit UUID string that represents the unit of measurement for this characteristic's value.

Syntax

__property String CharacteristicValueUnit[int CharacteristicIndex] = { read=FCharacteristicValueUnit };

Default Value

""

Remarks

The 128-bit UUID string that represents the unit of measurement for this characteristic's value.

The CharacteristicIndex parameter specifies the index of the item in the array. The size of the array is controlled by the CharacteristicCount property.

This property is read-only and not available at design time.

Data Type

String

DescriptorCount Property (BLEClient Component)

The number of records in the Descriptor arrays.

Syntax

__property int DescriptorCount = { read=FDescriptorCount };

Default Value

0

Remarks

This property controls the size of the following arrays:

• DescriptorDescription
• DescriptorId
• DescriptorUuid

The array indices start at 0 and end at DescriptorCount - 1.

This property is read-only and not available at design time.

Data Type

Integer

DescriptorDescription Property (BLEClient Component)

This descriptor's Bluetooth SIG user-friendly name, if one is defined.

Syntax

__property String DescriptorDescription[int DescriptorIndex] = { read=FDescriptorDescription };

Default Value

""

Remarks

This descriptor's Bluetooth SIG user-friendly name, if one is defined.

The DescriptorIndex parameter specifies the index of the item in the array. The size of the array is controlled by the DescriptorCount property.

This property is read-only and not available at design time.

Data Type

String

DescriptorId Property (BLEClient Component)

An identification string which uniquely identifies this instance of this descriptor.

Syntax

__property String DescriptorId[int DescriptorIndex] = { read=FDescriptorId };

Default Value

""

Remarks

An identification string which uniquely identifies this instance of this descriptor.

This identification string is guaranteed to be unchanged while the component remains connected to the device.

The DescriptorIndex parameter specifies the index of the item in the array. The size of the array is controlled by the DescriptorCount property.

This property is read-only and not available at design time.

Data Type

String

DescriptorUuid Property (BLEClient Component)

This descriptor's 128-bit UUID string.

Syntax

__property String DescriptorUuid[int DescriptorIndex] = { read=FDescriptorUuid };

Default Value

""

Remarks

This descriptor's 128-bit UUID string.

The DescriptorIndex parameter specifies the index of the item in the array. The size of the array is controlled by the DescriptorCount property.

This property is read-only and not available at design time.

Data Type

String

Scanning Property (BLEClient Component)

Whether or not the component is currently scanning for servers.

Syntax

__property bool Scanning = { read=FScanning };

Default Value

false

Remarks

This property indicates whether or not the component is currently scanning for servers. While the component is scanning, the Advertisement event will be fired whenever an advertisement from a remote device is received.

Refer to the StartScanning method for more information.

This property is read-only and not available at design time.

Data Type

Boolean

ServerId Property (BLEClient Component)

Platform-specific string identifying the currently connected server.

Syntax

__property String ServerId = { read=FServerId };

Default Value

""

Remarks

When the component is connected to a server, this property contains the platform-specific server identification string.

Note that this value is not guaranteed to be the same at any point in time for a specific server device.

This property is read-only and not available at design time.

Data Type

String

ServerName Property (BLEClient Component)

Local name of the currently connected server.

Syntax

__property String ServerName = { read=FServerName };

Default Value

""

Remarks

When the component is connected to a server, this property contains the server's local name.

If the server's name changes while you're connected to it, the ServerUpdate event will fire with the Name parameter populated, and the new value will be reflected here.

This property is read-only and not available at design time.

Data Type

String

Service Property (BLEClient Component)

The currently selected service's Id.

Syntax

__property String Service = { read=FService, write=FSetService };

Default Value

""

Remarks

Setting the Service property to the Id of a discovered service allows you to inspect the characteristics which have been discovered for it using the Characteristics collection.

Service can either be set to the Id of a service which has been discovered for the currently connected server, or to empty string. Setting Service will automatically reset Characteristic to empty string.

This property is automatically set when you call the Select method.

This property is not available at design time.

Data Type

String

ServiceCount Property (BLEClient Component)

The number of records in the Service arrays.

Syntax

__property int ServiceCount = { read=FServiceCount };

Default Value

0

Remarks

This property controls the size of the following arrays:

• ServiceDescription
• ServiceId
• ServiceIncludedSvcIds
• ServiceParentSvcIds
• ServiceUuid

The array indices start at 0 and end at ServiceCount - 1.

This property is read-only and not available at design time.

Data Type

Integer

ServiceDescription Property (BLEClient Component)

This service's Bluetooth SIG user-friendly name, if one is defined.

Syntax

__property String ServiceDescription[int ServiceIndex] = { read=FServiceDescription };

Default Value

""

Remarks

This service's Bluetooth SIG user-friendly name, if one is defined.

The ServiceIndex parameter specifies the index of the item in the array. The size of the array is controlled by the ServiceCount property.

This property is read-only and not available at design time.

Data Type

String

ServiceId Property (BLEClient Component)

An identification string which uniquely identifies this instance of this service.

Syntax

__property String ServiceId[int ServiceIndex] = { read=FServiceId };

Default Value

""

Remarks

An identification string which uniquely identifies this instance of this service.

This identification string is guaranteed to be unchanged while the component remains connected to the device.

The ServiceIndex parameter specifies the index of the item in the array. The size of the array is controlled by the ServiceCount property.

This property is read-only and not available at design time.

Data Type

String

ServiceIncludedSvcIds Property (BLEClient Component)

If any included services have been discovered for this service, this is a comma-separated list of their Ids.

Syntax

__property String ServiceIncludedSvcIds[int ServiceIndex] = { read=FServiceIncludedSvcIds };

Default Value

""

Remarks

If any included services have been discovered for this service, this is a comma-separated list of their Ids.

If additional included services are discovered later, their Ids will be appended.

The ServiceIndex parameter specifies the index of the item in the array. The size of the array is controlled by the ServiceCount property.

This property is read-only and not available at design time.

Data Type

String

ServiceParentSvcIds Property (BLEClient Component)

If this services is included by any other services, this is a comma-separated list of those services' Ids.

Syntax

__property String ServiceParentSvcIds[int ServiceIndex] = { read=FServiceParentSvcIds };

Default Value

""

Remarks

If this services is included by any other services, this is a comma-separated list of those services' Ids.

If it is discovered later that additional services include this service, their Ids will be appended.

The ServiceIndex parameter specifies the index of the item in the array. The size of the array is controlled by the ServiceCount property.

This property is read-only and not available at design time.

Data Type

String

ServiceUuid Property (BLEClient Component)

This service's 128-bit UUID string.

Syntax

__property String ServiceUuid[int ServiceIndex] = { read=FServiceUuid };

Default Value

""

Remarks

This service's 128-bit UUID string.

The ServiceIndex parameter specifies the index of the item in the array. The size of the array is controlled by the ServiceCount property.

This property is read-only and not available at design time.

Data Type

String

Timeout Property (BLEClient Component)

A timeout for the component.

Syntax

__property int Timeout = { read=FTimeout, write=FSetTimeout };

Default Value

60

Remarks

If the Timeout property is set to 0, all operations will run uninterrupted until successful completion or an error condition is encountered (except the PostValue method, which always returns immediately).

If Timeout is set to a positive value, the component will wait for a maximum of Timeout seconds since the beginning of the operation. If Timeout expires, and the operation is not yet complete, the component raises an exception.

The default value for the Timeout property is 60 (seconds).

Data Type

Integer

CheckCharacteristicSubscribed Method (BLEClient Component)

Checks to see if the component is subscribed to a characteristic.

Syntax

bool __fastcall CheckCharacteristicSubscribed(int index);

Remarks

This method is used to see if the component is subscribed to a characteristic. The method uses the given index parameter to find the characteristic at the index of the Characteristics property. The method will then return a bool value based on whether the client is currently subscribed to that characteristic.

Config Method (BLEClient Component)

Sets or retrieves a configuration setting.

Syntax

String __fastcall Config(String ConfigurationString);

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Connect Method (BLEClient Component)

Connect to a BLE GATT server based on its identifier.

Syntax

void __fastcall Connect(String ServerId);

Remarks

This method will attempt to connect to the BLE GATT server represented by the platform-specific identifier supplied in the ServerId parameter. The Connected event will be fired when the connection attempt finishes, and will contain additional information if the attempt failed.

If the component is connected to a server already when Connect is called, and the given ServerId is different than the currently connected server's ServerId, it will attempt to gracefully disconnect prior to initiating a new connection.

Calling Connect does nothing if ServerId is empty or matches the currently connected server's ServerId.

If Connect is called while the component is Scanning, the component will stop scanning prior to attempting to initiate a connection.

Note that there are a variety of reasons that a connection to a server may fail, not the least of which includes the server device being out of range of the client device. For the best results, it is recommended that you scan for devices before attempting a connection. Also note that the device identifier is a platform-specific value which is not guaranteed to be the same at any given point in time for any specific server device.

Connecting and Disconnecting // Connect to our TI SensorTag device. bleclient1.Connect("546C0E795800"); // Use BLEClient... // Disconnect from the device. bleclient1.Disconnect();

Disconnect Method (BLEClient Component)

Disconnects from the remote server.

Syntax

void __fastcall Disconnect();

Remarks

This method disconnects from the remote server and clears all service, characteristic, and descriptor data from the component. The Disconnected event will be fired when the component has disconnected from the remote device.

Refer to the Connect method for more information.

Discover Method (BLEClient Component)

Convenience method to discover multiple levels of the GATT object hierarchy at once.

Syntax

void __fastcall Discover(String ServiceUuids, String CharacteristicUuids, bool DiscoverDescriptors, String IncludedByServiceId);

Remarks

This method can be used in place of individual calls to the DiscoverServices, DiscoverCharacteristics, and DiscoverDescriptors methods in order to discover GATT objects from multiple levels of the GATT hierarchy at once.

To discover root services, their characteristics, and those characteristics' descriptors, you can:

• Pass a comma-separated list of service UUIDs for the services which you are interested in to the ServiceUuids parameter.
• Pass a comma-separated list of characteristic UUIDs for the characteristics which you are interested in (for any and all services which could be discovered) to the CharacteristicUuids parameter.
• Pass either true or false to the DiscoverDescriptors parameter, based on whether or not you wish to discover descriptors for discovered characteristics.
• Pass the empty string to the IncludedByServiceId parameter.

If you wish to discover included services, their characteristics, and those characteristics' descriptors, the above still applies, but you should pass the Id of an already discovered service to the IncludedByServiceId parameter.

You have the option of passing the empty string to either, or both, of the ServiceUuids and CharacteristicUuids parameters if you do not wish to limit your discovery to specific services and/or characteristics, but doing so is strongly discouraged due to the additional power consumption that will result.

During the discovery process, the Discovered event will fire once for each GATT object discovered. You may control whether it fires when a GATT object is rediscovered by setting the IncludeRediscovered configuration setting.

Keep in mind that having any of the following configuration settings enabled when you call this method may cause additional, unwanted power consumption: AutoDiscoverCharacteristics, AutoDiscoverDescriptors, or AutoDiscoverIncludedServices.

Multi-Level Discovery string serviceUUIDs = "180A,F000AA70-0451-4000-B000-000000000000,F000AA20-0451-4000-B000-000000000000"; string characteristicUUIDs = ""; //All Characteristics bool discoverDescriptors = true; string includedByServiceId = ""; //No included services // This will discover all characteristics and descriptors for specific services. bleclient1.Discover(serviceUUIDs, characteristicUUIDs, discoverDescriptors, includedByServiceId); // This will discover everything on the server, but won't discover // the "includes"/"included by" service relationships. bleclient1.Discover("", "", true, "");

DiscoverCharacteristics Method (BLEClient Component)

Used to discover characteristics for a specific service.

Syntax

void __fastcall DiscoverCharacteristics(String ServiceId, String CharacteristicUuids);

Remarks

This method is used to discover characteristics that belong to the service represented by ServiceId. Discovered characteristics' data will be used to populate the Characteristics collection property when the Service property is set to the applicable service Id.

It is recommended that you pass a comma-separated list of characteristic UUIDs for the CharacteristicUuids parameter in order to limit discovery to just the characteristics that you are interested in. You may also pass the empty string to discover all of the service's characteristics, but doing so will result in higher power consumption.

During the discovery process, the Discovered event will fire once for each characteristic discovered. You may control whether it fires when a characteristic is rediscovered by setting the IncludeRediscovered configuration setting.

Keep in mind that having any of the following configuration settings enabled when you call this method may cause additional, unwanted power consumption: AutoDiscoverCharacteristics, AutoDiscoverDescriptors, or AutoDiscoverIncludedServices.

Characteristic Discovery // Discovered event handler. bleclient1.OnDiscovered += (s, e) => { Console.WriteLine("Characteristic discovered:" + "\r\n\tOwning Service Id: " + e.ServiceId + "\r\n\tCharacteristic Id: " + e.CharacteristicId + // The discovered characteristic's 128-bit UUID string, in the format // "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX" "\r\n\tUUID: " + e.Uuid + // For standard characteristics whose UUIDs are defined by the Bluetooth SIG, // the Description event parameter will contain the name of the characteristic. "\r\n\tDescription: " + e.Description); }; // Discover all characteristics for the service whose Id is "000900000000". // (On our CC2650STK TI SensorTag, this is the Device Information Service.) bleclient1.DiscoverCharacteristics("000900000000", "");

Filtered Characteristic Discovery // Discover specific characteristics for the service whose Id is "000900000000". // (On our CC2650STK TI SensorTag, this is the Device Information Service.) // This will cause the System Id, Model Number String, and Manufacturer Name String // characteristics to be discovered, respectively. bleclient1.DiscoverCharacteristics("000900000000", "2A23,2A24,2A29");

DiscoverDescriptors Method (BLEClient Component)

Used to discover all descriptors for a specific characteristic.

Syntax

void __fastcall DiscoverDescriptors(String ServiceId, String CharacteristicId);

Remarks

This method is used to discover all descriptors that belong to the characteristic represented by CharacteristicId (which is owned by the service represented by ServiceId). Discovered descriptors' data will be used to populate the Descriptors collection property when the Characteristic property is set to the applicable characteristic Id.

During the discovery process, the Discovered event will fire once for each descriptor discovered. You may control whether it fires when a descriptor is rediscovered by setting the IncludeRediscovered configuration setting.

Keep in mind that having any of the following configuration settings enabled when you call this method may cause additional, unwanted power consumption: AutoDiscoverCharacteristics, AutoDiscoverDescriptors, or AutoDiscoverIncludedServices.

Descriptor Discovery // Discovered event handler. bleclient1.OnDiscovered += (s, e) => { Console.WriteLine("Descriptor discovered:" + "\r\n\tOwning Service Id: " + e.ServiceId + "\r\n\tOwning Characteristic Id: " + e.CharacteristicId + "\r\n\tDescriptor Id: " + e.DescriptorId + // The discovered descriptor's 128-bit UUID string, in the format // "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX" "\r\n\tUUID: " + e.Uuid + // For standard descriptors whose UUIDs are defined by the Bluetooth SIG, // the Description event parameter will contain the name of the descriptor. "\r\n\tDescription: " + e.Description); }; // Discover all descriptors for characteristic Id "001C001D0000", owned by // service Id "001C00000000". (On our CC2650STK TI SensorTag, this is the // Battery Level characteristic, which is owned by the Battery Service.) bleclient1.DiscoverDescriptors("001C00000000", "001C001D0000");

DiscoverServices Method (BLEClient Component)

Used to discover services for the currently connected server.

Syntax

void __fastcall DiscoverServices(String ServiceUuids, String IncludedByServiceId);

Remarks

This method is used to discover root services on the currently connected server when empty string is passed for the IncludedByServiceId parameter. Passing the Id of an already-discovered service instead will cause the component to discover services included by that service.

All discovered services, root or otherwise, are added to the Services collection property.

It is recommended that you pass a comma-separated list of service UUIDs for the ServiceUuids parameter in order to limit discovery to just the services that you are interested in. You may also pass the empty string to discover all of the server's services (or all of a service's included services), but doing so will result in much higher power consumption.

During the discovery process, the Discovered event will fire once for each service discovered. You may control whether it fires when a service is rediscovered by setting the IncludeRediscovered configuration setting.

Keep in mind that having any of the following configuration settings enabled when you call this method may cause additional, unwanted power consumption: AutoDiscoverCharacteristics, AutoDiscoverDescriptors, or AutoDiscoverIncludedServices.

Service Discovery // Discovered event handler. bleclient1.OnDiscovered += (s, e) => { Console.WriteLine("Service discovered:" + "\r\n\tService Id: " + e.ServiceId + // The discovered service's 128-bit UUID string, in the format // "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX" "\r\n\tUUID: " + e.Uuid + // For standard services whose UUIDs are defined by the Bluetooth SIG, // the Description event parameter will contain the name of the service. "\r\n\tDescription: " + e.Description); }; // Discover all root services. bleclient1.DiscoverServices("", ""); // Discover all services included by a discovered service whose Id is "000100000000". bleclient1.DiscoverServices("", "000100000000");

Filtered Service Discovery // Discover specific root services. These three UUIDs will cause the Device Information, // Luxometer, and Humidity services to be discovered on our CC2650STK TI SensorTag. // (Since the latter two are non-standard, you have to use their full UUIDs.) bleclient1.DiscoverServices("180A,F000AA70-0451-4000-B000-000000000000,F000AA20-0451-4000-B000-000000000000", ""); // Discover specific services included by a discovered service whose Id is "000100000000". // (The TI SensorTag doesn't have any included services, this is just an example.) bleclient1.DiscoverServices("FFFFFFFF-9000-4000-B000-000000000000", "000100000000")

DoEvents Method (BLEClient Component)

This method processes events from the internal message queue.

Syntax

void __fastcall DoEvents();

Remarks

When DoEvents is called, the component processes any available events. If no events are available, it waits for a preset period of time, and then returns.

PostValue Method (BLEClient Component)

Write the value of a characteristic without expecting a response.

Syntax

void __fastcall PostValue(String ServiceId, String CharacteristicId, DynamicArray<Byte> Value);

Remarks

This method is used to write the value of a characteristic, but unlike WriteValue it instructs the server not to send a response, even if the write request fails. This method will return immediately after the request is sent, regardless of the current Timeout value.

If your use-case doesn't require confirmation of characteristic value writes, this method is preferred; it allows both devices (but especially the server) to save power by keeping the BLE radio hardware turned off.

If you do require confirmation of characteristic value writes, or need to write a descriptor's value, use the WriteValue method.

Posting Values // The CC2650STK TI SensorTag doesn't have any characteristics which support // write without response, so this is just an example. bleclient1.PostValue("00AA00000000", "00AA00BB0000", new byte[] { 0x1, 0x2, 0x3 });

QueryCharacteristicCachedVal Method (BLEClient Component)

Reads and returns a characteristic value from the value cache.

Syntax

DynamicArray<Byte> __fastcall QueryCharacteristicCachedVal(int index);

Remarks

This method will return the cached value for the characteristic. The method uses the given index parameter to find the characteristic at the index of the Characteristics property. The method then uses that characteristic to retrieve information from the value cache. 

QueryDescriptorCachedVal Method (BLEClient Component)

Reads and returns a descriptor value from the value cache.

Syntax

DynamicArray<Byte> __fastcall QueryDescriptorCachedVal(int index);

Remarks

This method will return the cached value for the descriptor. The method uses the given index parameter to find the descriptor at the index of the Descriptors property. The method then uses that descriptor to retrieve information from the value cache. 

ReadValue Method (BLEClient Component)

Read the value of a characteristic or descriptor from the server.

Syntax

DynamicArray<Byte> __fastcall ReadValue(String ServiceId, String CharacteristicId, String DescriptorId);

Remarks

This method is used to read the value of a characteristic or a descriptor directly from the server, bypassing the platform's cache in the process.

To read the value of a characteristic, pass the Ids of it and its owning service for the CharacteristicId and ServiceId parameters, and pass empty string for the DescriptorId parameter. To read the value of a descriptor, do the same thing, but pass the descriptor's Id for the DescriptorId parameter too.

If the read request is successful, the read value will be returned and the Value event will be fired. In addition, the platform will cache the value; you can retrieve the cached for a characteristic using CharacteristicCachedValue or for a descriptor using DescriptorCachedValue.

If the read request fails, the Error event will be fired and the component raises an exception.

If the value of a characteristic changes often, prefer subscribing to the characteristic over polling in order to prevent unnecessary power consumption. Refer to the Subscribe method for more information.

Reading Live Values // Value event handler. bleclient1.OnValue += (s, e) => { if (string.IsNullOrEmpty(e.DescriptorId)) { Console.WriteLine("Read value {" + BitConverter.ToString(e.ValueB) + "} for characteristic with UUID " + e.Uuid); } else { Console.WriteLine("Read value {" + BitConverter.ToString(e.ValueB) + "} for descriptor with UUID " + e.Uuid); } }; // Print the live value for the Battery Level characteristic. These Ids // are correct for our CC2650STK TI SensorTag, but yours might differ. byte[] rawBatteryVal = bleclient1.ReadValue("001C00000000", "001C001D0000", ""); Console.WriteLine("Battery Level Value: " + (int)rawBatteryVal[0]); // Print the live value for the Characteristic Presentation Format descriptor on // the Battery Level characteristic. Again, your Ids might differ. byte[] rawBatteryPF = bleclient1.ReadValue("001C00000000", "001C001D0000", "001C001D0021"); Console.WriteLine("Battery Level Presentation Format bytes: " + BitConverter.ToString(rawBatteryPF));

Reading Cached Values // Print the cached value for the Luxometer Data characteristic (which you can // assume we've already found and assigned to a variable called "luxChara"). byte[] rawLuxVal = luxChara.CachedValueB; ushort luxVal = BitConverter.ToUInt16(rawLuxVal, 0); Console.WriteLine("Luxometer Value: " + luxVal); // Print the cached value for the Client Characteristic Configuration descriptor on // the Luxometer Data characteristic (again, assume it's stored in "luxCCCD"). byte[] rawLuxCCCD = luxCCCD.CachedValueB; Console.WriteLine("Luxometer CCCD bytes: " + BitConverter.ToString(rawLuxCCCD));

Select Method (BLEClient Component)

Used to set the currently selected service and characteristic by their Ids.

Syntax

void __fastcall Select(String ServiceId, String CharacteristicId);

Remarks

This is a convenience method used to select a specific service and/or characteristic.

To select just a service, only pass the desired service Id for ServiceId; pass empty string for CharacteristicId. To select a characteristic, pass both of the Ids.

As long as both of the Ids are valid, the Service and Characteristic properties will be set accordingly (Characteristic is cleared if a characteristic Id isn't given).

An error will be thrown if any of the Ids aren't valid, or if an invalid combination of Ids is passed.

StartScanning Method (BLEClient Component)

Causes the component to begin scanning for BLE GATT servers.

Syntax

void __fastcall StartScanning(String ServiceUuids);

Remarks

This method causes the component to start scanning for BLE GATT servers, optionally filtered to include only servers which are advertising one or more services of interest.

To scan for all servers, pass empty string as the ServiceUuids parameter.

To scan for only servers advertising specific services, pass a comma-separated list of service UUIDs as the ServiceUuids parameter. (Only servers advertising all of the given services will be detected. Be aware that, due to the limited space in an advertisement packet, it's common for servers to support more services than they advertise.)

The StartScan event will be fired when the scanning has begun, after which the Advertisement event is fired whenever an advertisement from a server is received; the Error event is fired if an error occurs.

If you wish to use active scanning, enable the ActiveScanning property before you call StartScanning (refer to its documentation for more information).

You may start scanning while already connected to a server, but the component will stop scanning automatically if you attempt to initiate a new server connection (regardless of whether or not that connection attempt ends up succeeding).

Please be aware that scanning is a power-intensive activity, and you should call the StopScanning method as soon as is appropriate in order to prevent unnecessary power consumption.

Calling StartScanning when the component is already scanning does nothing.

Basic Scanning and Advertisement Handling Example // StartScan event handler. bleclient1.OnStartScan += (s, e) => Console.WriteLine("Scanning has started"); // StopScan event handler. bleclient1.OnStopScan += (s, e) => Console.WriteLine("Scanning has stopped"); // Advertisement event handler. bleclient1.OnAdvertisement += (s, e) => { // Your application should make every effort to handle the Advertisement event quickly. // BLEClient fires it as often as necessary, often multiple times per second. Console.WriteLine("Advertisement Received:" + "\r\n\tServerId: " + e.ServerId + "\r\n\tName: " + e.Name + "\r\n\tRSSI: " + e.RSSI + "\r\n\tTxPower: " + e.TxPower + "\r\n\tServiceUuids: " + e.ServiceUuids + "\r\n\tServicesWithData: " + e.ServicesWithData + "\r\n\tSolicitedServiceUuids: " + e.SolicitedServiceUuids + "\r\n\tManufacturerCompanyId: " + e.ManufacturerCompanyId + // We use BitConverter.ToString() to print data as hex bytes; this also prevents // an issue where the string could be cut off early if the data has a 0 byte in it. "\r\n\tManufacturerCompanyData: " + BitConverter.ToString(e.ManufacturerDataB) + "\r\n\tIsConnectable: " + e.IsConnectable + "\r\n\tIsScanResponse: " + e.IsScanResponse); }; // Scan for all devices. bleclient1.StartScanning(""); // Wait a while... bleclient1.StopScanning();

Filtered Scanning Example // Scan for devices which are advertising at least these UUIDs. You can use a mixture // of 16-, 32-, and 128-bit UUID strings, they'll be converted to 128-bit internally. bleclient1.StartScanning("180A,0000180F,00001801-0000-1000-8000-00805F9B34FB"); // ... bleclient1.StopScanning();

StopScanning Method (BLEClient Component)

Causes the component to stop scanning for BLE GATT servers.

Syntax

void __fastcall StopScanning();

Remarks

This method will request that the component stop scanning for BLE GATT servers if it is currently doing so, otherwise it will do nothing. The StopScan event will fire when the scanning has stopped.

Note that scanning may be stopped automatically by the platform under certain conditions; the StopScan event will contain the error code and description if applicable.

You can check the Scanning property to determine whether or not the component is currently scanning.

Subscribe Method (BLEClient Component)

Subscribes to value updates for the specified characteristic.

Syntax

void __fastcall Subscribe(String ServiceId, String CharacteristicId);

Remarks

This method will subscribe the component to value updates for the characteristic whose Id is passed to CharacteristicId (which is owned by the service specified by ServiceId), as long as the characteristic supports it.

You can check a characteristic's CharacteristicCanSubscribe property to determine whether or not it supports subscriptions.

The Subscribed event will fire whenever you subscribe to a characteristic. While subscribed to a characteristic, the Value event will be fired each time the server sends an updated value for it (and its cached value will be updated as well).

The characteristic's CharacteristicSubscribed property can be used to determine whether or not the component is currently subscribed to a characteristic. You can also set it to true or false, which will automatically call Subscribe or Unsubscribe.

An error will be thrown if either of the given Ids are invalid, if the characteristic does not support subscribing for updates, or if there is an issue while trying to subscribe. Trying to subscribe to an already-subscribed characteristic does nothing.

Subscriptions // Subscribed event handler. bleclient1.OnSubscribed += (s, e) => { Console.WriteLine("Subscribed to characteristic:" + "\r\n\tID: " + e.CharacteristicId + "\r\n\tUUID: " + e.Uuid + "\r\n\tDescription: " + e.Description); }; // Unsubscribed event handler. bleclient1.OnUnsubscribed += (s, e) => { Console.WriteLine("Unsubscribed from characteristic:" + "\r\n\tID: " + e.CharacteristicId + "\r\n\tUUID: " + e.Uuid + "\r\n\tDescription: " + e.Description); }; // Value event handler. bleclient1.OnValue += (s, e) => { Console.WriteLine("Value update received for characteristic: " + "\r\n\tID: " + e.CharacteristicId + "\r\n\tUUID: " + e.Uuid + "\r\n\tDescription: " + e.Description + "\r\n\tValue: " + BitConverter.ToString(e.ValueB)); }; // Assume that we've already found the Luxometer Data characteristic, // its owning service, and the Client Characteristic Configuration // descriptor on it; and we've stored them in variables called "luxSvc", // "luxData", and "luxCCCD". // Subscribe and unsubscribe using methods. bleclient1.Subscribe(luxSvc.Id, luxData.Id); // ... bleclient1.Unsubscribe(luxSvc.Id, luxData.Id); // Subscribe and unsubscribe using the "Subscribed" field. luxData.Subscribed = true; // ... luxData.Subscribed = false; // Subscribe and unsubscribe by writing directly to the CCCD. bleclient1.WriteValue(luxSvc.Id, luxData.Id, luxCCCD.Id, new byte[] { 1, 0 }); // ... bleclient1.WriteValue(luxSvc.Id, luxData.Id, luxCCCD.Id, new byte[] { 0, 0 });

Unsubscribe Method (BLEClient Component)

Unsubscribes from value updates for one or more characteristics.

Syntax

void __fastcall Unsubscribe(String ServiceId, String CharacteristicId);

Remarks

This method will unsubscribe from value updates for the characteristic represented by CharacteristicId (which is owned by the service specified by ServiceId). The Unsubscribed event will fire each time you unsubscribe from a characteristic.

Passing empty string for CharacteristicId will cause the component to unsubscribe from any characteristic it is subscribed to in the specified service. Passing empty string for both parameters does the same, but for all services. (Unsubscribing en masse may take time since every subscribe/unsubscribe operation requires a write request and response behind the scenes.)

An error will be thrown if either of the given Ids are invalid (when both are passed), if only CharacteristicId is passed, if the characteristic does not support subscribing for updates, or if there is an issue while trying to unsubscribe.

Refer to the Subscribe method for more information.

WriteValue Method (BLEClient Component)

Write the value of a characteristic or descriptor.

Syntax

void __fastcall WriteValue(String ServiceId, String CharacteristicId, String DescriptorId, DynamicArray<Byte> Value);

Remarks

This method is used to write the value of a characteristic or descriptor. The method will return and the WriteResponse event will fire if the write is a success. If the write fails, the Error event will fire and the component raises an exception.

To write the value of a characteristic, pass the Ids of it and its owning service for the CharacteristicId and ServiceId parameters, and pass empty string for the DescriptorId parameter. To write the value of a descriptor, do the same thing, but pass the descriptor's Id for the DescriptorId parameter too.

If your use-case doesn't require confirmation of characteristic value writes, prefer the PostValue method in order to reduce power consumption.

Writing Values // WriteResponse event handler. bleclient1.OnWriteResponse += (s, e) => { if (string.IsNullOrEmpty(e.DescriptorId)) { Console.WriteLine("Successfully wrote to characteristic with UUID " + e.Uuid); } else { Console.WriteLine("Successfully wrote to descriptor with UUID " + e.Uuid); } }; // Write to the Luxometer Config characteristic. These Ids are correct // for our CC2650STK TI SensorTag, but yours might differ. bleclient1.WriteValue("004200000000", "004200460000", "", new byte[] { 0x1 }); // Write to the Client Characteristic Configuration descriptor on the // Luxometer Data characteristic. Again, your Ids might differ. bleclient1.WriteValue("004200000000", "004200430000", "004200430045", new byte[] { 0x1 });

Advertisement Event (BLEClient Component)

Fired when an advertisement packet is received during scanning.

Syntax

typedef struct {
  String ServerId;
  String Name;
  int RSSI;
  int TxPower;
  String ServiceUuids;
  String ServicesWithData;
  String SolicitedServiceUuids;
  int ManufacturerCompanyId;
  String ManufacturerData;
  DynamicArray<Byte> ManufacturerDataB;
  bool IsConnectable;
  bool IsScanResponse;
} TiplBLEClientAdvertisementEventParams;
typedef void __fastcall (__closure *TiplBLEClientAdvertisementEvent)(System::TObject* Sender, TiplBLEClientAdvertisementEventParams *e);
__property TiplBLEClientAdvertisementEvent OnAdvertisement = { read=FOnAdvertisement, write=FOnAdvertisement };

Remarks

The Advertisement event is fired each time an advertisement is received while the component is Scanning for servers to connect to. Based on the information in the advertisement, you can decide whether or not you wish to connect to the associated device (if it is connectable).

Not all of the parameters are relevant for all platforms. Additionally, since advertisement packets are somewhat flexible in their contents, it is not guaranteed that every parameter relevant to your platform will be populated for every advertisement. Please refer to the following table for descriptions of the parameters:

Setting the ServiceData configuration setting to any of the service UUIDs in the ServicesWithData parameter will return the associated data.

You can use the ManufacturerDataCount configuration setting to determine whether the advertisement contains multiple manufacturer data sections; if it does, the ManufacturerData and ManufacturerCompanyId configuration settings can be used to iterate over them.

Note that all of the configuration settings mentioned above are only valid while you are within the Advertisement event handler.

Please refer to the following table to determine which parameters are relevant for your platform:

Refer to the StartScanning method for more information.

Connected Event (BLEClient Component)

Fired immediately after a connection to a remote device completes (or fails).

Syntax

typedef struct {
  int StatusCode;
  String Description;
} TiplBLEClientConnectedEventParams;
typedef void __fastcall (__closure *TiplBLEClientConnectedEvent)(System::TObject* Sender, TiplBLEClientConnectedEventParams *e);
__property TiplBLEClientConnectedEvent OnConnected = { read=FOnConnected, write=FOnConnected };

Remarks

If the connection is made successfully, StatusCode is 0 and Description is "OK".

If the connection fails, StatusCode has the error code returned by the Bluetooth stack. Description contains a description of this code.

Refer to the Connect method for more information.

Disconnected Event (BLEClient Component)

Fired when the component has been disconnected from the remote device.

Syntax

typedef struct {
  int StatusCode;
  String Description;
} TiplBLEClientDisconnectedEventParams;
typedef void __fastcall (__closure *TiplBLEClientDisconnectedEvent)(System::TObject* Sender, TiplBLEClientDisconnectedEventParams *e);
__property TiplBLEClientDisconnectedEvent OnDisconnected = { read=FOnDisconnected, write=FOnDisconnected };

Remarks

If the connection is broken normally, StatusCode is 0 and Description is "OK".

If the connection is broken for any other reason, StatusCode has the error code returned by the Bluetooth stack. Description contains a description of this code.

Refer to the Disconnect section for more information.

Discovered Event (BLEClient Component)

Fired when the component discovers a service, characteristic, or descriptor.

Syntax

typedef struct {
  int GattType;
  String ServiceId;
  String CharacteristicId;
  String DescriptorId;
  String Uuid;
  String Description;
} TiplBLEClientDiscoveredEventParams;
typedef void __fastcall (__closure *TiplBLEClientDiscoveredEvent)(System::TObject* Sender, TiplBLEClientDiscoveredEventParams *e);
__property TiplBLEClientDiscoveredEvent OnDiscovered = { read=FOnDiscovered, write=FOnDiscovered };

Remarks

This event is fired during any discovery process to indicate that the component has discovered a service, characteristic, or descriptor. Discovery processes take place whenever Discover, DiscoverServices, DiscoverCharacteristics, or DiscoverDescriptors is called.

GattType indicates what type of GATT object was discovered:

• 0 - Service
• 1 - Characteristic
• 2 - Descriptor

Uuid and Description are the UUID and Bluetooth SIG user-friendly name (if one is defined) of the discovered service, characteristic, or descriptor.

When a service is discovered:

• ServiceId is the Id of the newly discovered service.
• CharacteristicId is empty.
• DescriptorId is empty.

When a characteristic is discovered:

• ServiceId is the Id of the previously discovered service which owns the newly discovered characteristic.
• CharacteristicId is the Id of the newly discovered characteristic.
• DescriptorId is empty.

When a descriptor is discovered:

• ServiceId is the Id of the previously discovered service which owns the previously discovered characteristic.
• CharacteristicId is the Id of the previously discovered characteristic which owns the newly discovered descriptor.
• DescriptorId is the Id of the newly discovered descriptor.

Error Event (BLEClient Component)

Fired when information is available about errors during data delivery.

Syntax

typedef struct {
  int ErrorCode;
  String Description;
} TiplBLEClientErrorEventParams;
typedef void __fastcall (__closure *TiplBLEClientErrorEvent)(System::TObject* Sender, TiplBLEClientErrorEventParams *e);
__property TiplBLEClientErrorEvent OnError = { read=FOnError, write=FOnError };

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the component raises an exception.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Log Event (BLEClient Component)

Fires once for each log message.

Syntax

typedef struct {
  int LogLevel;
  String Message;
  String LogType;
} TiplBLEClientLogEventParams;
typedef void __fastcall (__closure *TiplBLEClientLogEvent)(System::TObject* Sender, TiplBLEClientLogEventParams *e);
__property TiplBLEClientLogEvent OnLog = { read=FOnLog, write=FOnLog };

Remarks

This events fires once for each log message generated by the component. The verbosity is controlled by the LogLevel setting.

LogLevel indicates the level of the Message. Possible values are:

The default log level, Info, provides information when most BLE operations begin and end, and should be sufficient to get a good idea of what the component is doing at a high level.

The Verbose log level adds a few extra operation timing messages, and adds more detail to some messages logged at the Info level.

The Debug log level causes the component to output as much information as possible about what it is doing at all times. All BLE communications, even those which are typically abstracted away by the API, are logged in full detail. Typically the additional information added by this log level is not helpful to the end user, and would only be necessary to capture if you wish to report an issue to the support team.

LogType identifies the type of log entry. Possible values are:

• Scanning: Messages relating to scanning and advertisements.
• Connection: Messages relating to connecting, disconnecting, and connection failures.
• Discovery: Messages relating to any service, characteristic, or descriptor discovery process.
• Read: Messages relating to reading values from the remote device.
• Write: Messages relating to writing values to the remote device.
• Subscriptions: Messages relating to subscribing to and unsubscribing from characteristics.
• Info, Verbose, and Debug: Miscellaneous messages fired at the applicable log level concerning internal component operations.

PairingRequest Event (BLEClient Component)

TBD.

Syntax

typedef struct {
  String ServerId;
  int PairingKind;
  String Pin;
  bool Accept;
} TiplBLEClientPairingRequestEventParams;
typedef void __fastcall (__closure *TiplBLEClientPairingRequestEvent)(System::TObject* Sender, TiplBLEClientPairingRequestEventParams *e);
__property TiplBLEClientPairingRequestEvent OnPairingRequest = { read=FOnPairingRequest, write=FOnPairingRequest };

Remarks

TBD.

ServerUpdate Event (BLEClient Component)

Fired when the currently connected server updates its name or available services.

Syntax

typedef struct {
  String Name;
  String ChangedServices;
} TiplBLEClientServerUpdateEventParams;
typedef void __fastcall (__closure *TiplBLEClientServerUpdateEvent)(System::TObject* Sender, TiplBLEClientServerUpdateEventParams *e);
__property TiplBLEClientServerUpdateEvent OnServerUpdate = { read=FOnServerUpdate, write=FOnServerUpdate };

Remarks

This event is fired under one of two conditions, both of which involve some sort of server-side change other than the value of a subscribed characteristic having changed (subscribed characteristic value updates are delivered through the Value event).

If the server's name has changed, this event is fired with the new name in the Name parameter, and the ServerName property is updated as well.

If the server's services have changed, this event is fired with a non-empty value in the ChangedServices parameter.

StartScan Event (BLEClient Component)

Fired when the component starts scanning.

Syntax

typedef struct {
  String ServiceUuids;
} TiplBLEClientStartScanEventParams;
typedef void __fastcall (__closure *TiplBLEClientStartScanEvent)(System::TObject* Sender, TiplBLEClientStartScanEventParams *e);
__property TiplBLEClientStartScanEvent OnStartScan = { read=FOnStartScan, write=FOnStartScan };

Remarks

This event is fired when the component starts scanning. ServiceUuids is a comma-separated list of 128-bit service UUIDs that the scan is being filtered by. Refer to the StartScanning method for more information.

StopScan Event (BLEClient Component)

Fired when the component stops scanning.

Syntax

typedef struct {
  int ErrorCode;
  String ErrorDescription;
} TiplBLEClientStopScanEventParams;
typedef void __fastcall (__closure *TiplBLEClientStopScanEvent)(System::TObject* Sender, TiplBLEClientStopScanEventParams *e);
__property TiplBLEClientStopScanEvent OnStopScan = { read=FOnStopScan, write=FOnStopScan };

Remarks

This event is fired when the component stops scanning. If the scanning stopped due to an error, the ErrorCode and ErrorDescription parameters will be set accordingly; otherwise they will be 0 and empty string. Refer to the StopScanning method for more information.

Subscribed Event (BLEClient Component)

Fired when the component has successfully subscribed to a characteristic.

Syntax

typedef struct {
  String ServiceId;
  String CharacteristicId;
  String Uuid;
  String Description;
} TiplBLEClientSubscribedEventParams;
typedef void __fastcall (__closure *TiplBLEClientSubscribedEvent)(System::TObject* Sender, TiplBLEClientSubscribedEventParams *e);
__property TiplBLEClientSubscribedEvent OnSubscribed = { read=FOnSubscribed, write=FOnSubscribed };

Remarks

This event is fired when the component has successfully subscribed to a characteristic.

Uuid and Description are the UUID and Bluetooth SIG user-friendly name (if one is defined) of the characteristic.

Refer to the Subscribe method for more information.

Unsubscribed Event (BLEClient Component)

Fired when the component has successfully unsubscribed from a characteristic.

Syntax

typedef struct {
  String ServiceId;
  String CharacteristicId;
  String Uuid;
  String Description;
} TiplBLEClientUnsubscribedEventParams;
typedef void __fastcall (__closure *TiplBLEClientUnsubscribedEvent)(System::TObject* Sender, TiplBLEClientUnsubscribedEventParams *e);
__property TiplBLEClientUnsubscribedEvent OnUnsubscribed = { read=FOnUnsubscribed, write=FOnUnsubscribed };

Remarks

This event is fired when the component has successfully unsubscribed from a characteristic.

Uuid and Description are the UUID and Bluetooth SIG user-friendly name (if one is defined) of the characteristic

Refer to the Unsubscribe method for more information.

Value Event (BLEClient Component)

Fired when a characteristic or descriptor value is received from the server.

Syntax

typedef struct {
  String ServiceId;
  String CharacteristicId;
  String DescriptorId;
  String Uuid;
  String Description;
  String Value;
  DynamicArray<Byte> ValueB;
} TiplBLEClientValueEventParams;
typedef void __fastcall (__closure *TiplBLEClientValueEvent)(System::TObject* Sender, TiplBLEClientValueEventParams *e);
__property TiplBLEClientValueEvent OnValue = { read=FOnValue, write=FOnValue };

Remarks

This event is fired to signify that a value has been received for a characteristic or descriptor. The DescriptorId parameter will be empty string if the value is for a characteristic.

Uuid and Description are the UUID and Bluetooth SIG user-friendly name (if one is defined) of the characteristic or descriptor.

There are three scenarios which can cause this event to fire:

• The server has responded to a read request for a characteristic.
• The server has responded to a read request for a descriptor.
• The server has sent an updated value for a subscribed characteristic.

Whenever a value is received for a characteristic or descriptor, the value that the platform has cached for it is updated as well. You can read the cached value for a characteristic using CharacteristicCachedValue, or for a descriptor using DescriptorCachedValue.

Refer to the ReadValue and/or Subscribe methods for more information.

WriteResponse Event (BLEClient Component)

Fired when the server acknowledges a successful value write request.

Syntax

typedef struct {
  String ServiceId;
  String CharacteristicId;
  String DescriptorId;
  String Uuid;
  String Description;
} TiplBLEClientWriteResponseEventParams;
typedef void __fastcall (__closure *TiplBLEClientWriteResponseEvent)(System::TObject* Sender, TiplBLEClientWriteResponseEventParams *e);
__property TiplBLEClientWriteResponseEvent OnWriteResponse = { read=FOnWriteResponse, write=FOnWriteResponse };

Remarks

This event is fired when the server acknowledges a successful value write request for a characteristic or descriptor.

ServiceId holds the Id of the service.

CharacteristicId holds the Id of the characteristic.

DescriptorId holds the Id of the descriptor. This is only populated when a descriptor value is written.

Uuid and Description are the UUID and Bluetooth SIG user-friendly name (if one is defined) of the characteristic or descriptor.

Note that this event is not fired if the write request was sent using PostValue, regardless of the outcome.

Refer to the WriteValue method for more information.

Config Settings (BLEClient Component)

The component accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

BLEClient Config Settings

Base Config Settings

Trappable Errors (BLEClient Component)

BLEClient Errors