Ping Component

Properties   Methods   Events   Config Settings   Errors  

The PING component encapsulates Internet Control Message Protocol (ICMP) ECHO functionality, which is used to check whether there is a communications link between two computers.

Syntax

nsoftware.IPWorks.Ping

Remarks

When the PingHost method is called with the Host parameter, or if RemoteHost is assigned an IP address or domain name, the component sends an ICMP ECHO packet to the remote host. The ResponseTime and ResponseSource properties are updated with the time of the roundtrip to the remote host and the address of the host actually sending the response.

The component operates synchronously by default (i.e., waits for a response before returning control to the caller); however, the component may also operate asynchronously (i.e., returns control immediately) by setting Timeout to 0. Please refer to the Timeout property for more information.

Property List

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

Method List

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

Event List

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

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

Active Property (Ping Component)

This property indicates whether the component is active.

Syntax

• C#
• VB.NET

public bool Active { get; set; }

Public Property Active As Boolean

Default Value

False

Remarks

This property indicates whether the component is currently active and can send or receive data.

The PingHost method will automatically change the value of this property to True.

Note: Use the Activate or Deactivate method to control whether the component is active.

This property is not available at design time.

Idle Property (Ping Component)

The current status of the component.

Syntax

• C#
• VB.NET

public bool Idle { get; }

Public ReadOnly Property Idle As Boolean

Default Value

True

Remarks

Idle will be False if the component is currently busy (communicating and/or waiting for an answer), and True at all other times.

This property is read-only.

LocalHost Property (Ping Component)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

• C#
• VB.NET

public string LocalHost { get; set; }

Public Property LocalHost As String

Default Value

""

Remarks

The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multi-homed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the component initiate connections (or accept in the case of server components) only through that interface.

If the component is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multi-homed hosts (machines with more than one IP interface).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

PacketSize Property (Ping Component)

This property includes the size of the packet to send as the ping request.

Syntax

• C#
• VB.NET

public int PacketSize { get; set; }

Public Property PacketSize As Integer

Default Value

64

Remarks

This property allows you to control the size of the data packet sent in the PingHost method. The default packet size is 64 bytes, with a minimum of 8 bytes (4 bytes of the ICMP header plus the ECHO identifier). The maximum value is 65520.

RemoteHost Property (Ping Component)

This property includes the address of the RemoteHost. Domain names are resolved to IP addresses.

Syntax

• C#
• VB.NET

public string RemoteHost { get; set; }

Public Property RemoteHost As String

Default Value

""

Remarks

This property specifies the IP address (IP number in dotted internet format) or the domain name of the remote host.

If this property is set to 255.255.255.255, the component broadcasts data on the local subnet.

If this property is set to a domain name, a DNS request is initiated. Upon successful termination of the request, the property is set to the corresponding address. If the search is not successful, the component throws an exception.

If UseConnection is True, this property must be set before the component is activated (Active is set to True).

RequestId Property (Ping Component)

This property includes a unique identifier for outgoing packets.

Syntax

• C#
• VB.NET

public int RequestId { get; }

Public ReadOnly Property RequestId As Integer

Default Value

0

Remarks

This property contains a unique identifier for outgoing packets. This property is useful during asynchronous ping operations. The RequestId parameter of the Response event is used to match requests with responses.

The identifier of the outgoing ping packet is provided in this property after the PingHost method returns.

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

ResponseSource Property (Ping Component)

This property includes the source of the last PING response.

Syntax

• C#
• VB.NET

public string ResponseSource { get; }

Public ReadOnly Property ResponseSource As String

Default Value

""

Remarks

This property contains the address of the host responding to the PING (ICMP ECHO) request. This may or may not be the host used in PingHost.

This property is read-only.

ResponseStatus Property (Ping Component)

This property includes the status of the last PING response.

Syntax

• C#
• VB.NET

public string ResponseStatus { get; }

Public ReadOnly Property ResponseStatus As String

Default Value

""

Remarks

This property contains the status of the last response. After PingHost has returned, this property will be populated with the status of the response. For responses without error, the value will be OK. In the case of an error, the value will hold a description of the error, such as Network Unreachable or Host Unreachable.

This property is read-only.

ResponseTime Property (Ping Component)

This property includes the time elapsed between sending the original packet and the remote host reply.

Syntax

• C#
• VB.NET

public int ResponseTime { get; }

Public ReadOnly Property ResponseTime As Integer

Default Value

0

Remarks

This property contains the time elapsed between sending the original packet and the remote host reply. The time value is expressed in milliseconds. The lowest resolution available depends on the resolution of the clock on the host system (normally between 10 ms and 20 ms).

This property is read-only.

Timeout Property (Ping Component)

A timeout for the component.

Syntax

• C#
• VB.NET

public int Timeout { get; set; }

Public Property Timeout As Integer

Default Value

60

Remarks

If the Timeout property is set to 0, all operations return immediately, potentially failing with a WOULDBLOCK error if data cannot be sent immediately.

If Timeout is set to a positive value, data is sent in a blocking manner and the component will wait for the operation to complete before returning control. The component will handle any potential WOULDBLOCK errors internally and automatically retry the operation for a maximum of Timeout seconds.

The component will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not "freeze" and remains responsive.

If Timeout expires, and the operation is not yet complete, the component throws an exception.

Please note that by default, all timeouts are inactivity timeouts, i.e. the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value for the Timeout property is 60 seconds.

TimeToLive Property (Ping Component)

This property includes the time-to-live (TTL) value for the ICMP packets sent by the component.

Syntax

• C#
• VB.NET

public int TimeToLive { get; set; }

Public Property TimeToLive As Integer

Default Value

0

Remarks

This method contains the time-to-live (TTL) value for the ICMP packets sent by the component. The TTL field of the ICMP packet is a counter limiting the lifetime of a packet.

Each router (or other module) that handles a packet decrements the TTL field by one or more if it holds the packet for more than one second. Thus, the TTL value is effectively a hop count limit on how far a datagram can propagate through the internet. When the TTL value is reduced to zero (or less), the packet is discarded.

If the value of the property is set to zero, then the default TTL value of the underlying Transmission Control Protocol (TCP)/IP subsystem will be used.

This property is not available at design time.

TypeOfService Property (Ping Component)

This property includes the type of ICMP message sent as a ping request.

Syntax

• C#
• VB.NET

public int TypeOfService { get; set; }

Public Property TypeOfService As Integer

Default Value

8

Remarks

This property contains the type of the ICMP message sent as a ping request. The default value is 8 (ECHO REQUEST).

This property is not available at design time.

Activate Method (Ping Component)

This method enables sending and receiving data.

Syntax

• C#
• VB.NET

public void Activate();

Async Version
public async Task Activate();
public async Task Activate(CancellationToken cancellationToken);

Public Sub Activate()

Async Version
Public Sub Activate() As Task
Public Sub Activate(cancellationToken As CancellationToken) As Task

Remarks

This method enables sending and receiving of data.

Note: Calling the PingHost method will automatically activate the component.

Config Method (Ping Component)

Sets or retrieves a configuration setting.

Syntax

• C#
• VB.NET

public string Config(string configurationString);

Async Version
public async Task<string> Config(string configurationString);
public async Task<string> Config(string configurationString, CancellationToken cancellationToken);

Public Function Config(ByVal ConfigurationString As String) As String

Async Version
Public Function Config(ByVal ConfigurationString As String) As Task(Of String)
Public Function Config(ByVal ConfigurationString As String, cancellationToken As CancellationToken) As Task(Of String)

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.

Deactivate Method (Ping Component)

This method disables sending and receiving data.

Syntax

• C#
• VB.NET

public void Deactivate();

Async Version
public async Task Deactivate();
public async Task Deactivate(CancellationToken cancellationToken);

Public Sub Deactivate()

Async Version
Public Sub Deactivate() As Task
Public Sub Deactivate(cancellationToken As CancellationToken) As Task

Remarks

This method disables sending and receiving data.

DoEvents Method (Ping Component)

Processes events from the internal message queue.

Syntax

• C#
• VB.NET

public void DoEvents();

Async Version
public async Task DoEvents();
public async Task DoEvents(CancellationToken cancellationToken);

Public Sub DoEvents()

Async Version
Public Sub DoEvents() As Task
Public Sub DoEvents(cancellationToken As CancellationToken) As Task

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.

Interrupt Method (Ping Component)

Interrupt the current method.

Syntax

• C#
• VB.NET

public void Interrupt();

Async Version
public async Task Interrupt();
public async Task Interrupt(CancellationToken cancellationToken);

Public Sub Interrupt()

Async Version
Public Sub Interrupt() As Task
Public Sub Interrupt(cancellationToken As CancellationToken) As Task

Remarks

If there is no method in progress, Interrupt simply returns, doing nothing.

PingHost Method (Ping Component)

This method pings a host.

Syntax

• C#
• VB.NET

public void PingHost(string host);

Async Version
public async Task PingHost(string host);
public async Task PingHost(string host, CancellationToken cancellationToken);

Public Sub PingHost(ByVal Host As String)

Async Version
Public Sub PingHost(ByVal Host As String) As Task
Public Sub PingHost(ByVal Host As String, cancellationToken As CancellationToken) As Task

Remarks

This method will ping a host. A valid internet domain name or address must be specified in Host, or an error will be returned.

A PING request (ICMP ECHO) is sent to the Host.

Example. Ping a Host:

PingControl.PingHost("MyHostName") ResponseTime = PingControl.ResponseTime

Reset Method (Ping Component)

Reset the component.

Syntax

• C#
• VB.NET

public void Reset();

Async Version
public async Task Reset();
public async Task Reset(CancellationToken cancellationToken);

Public Sub Reset()

Async Version
Public Sub Reset() As Task
Public Sub Reset(cancellationToken As CancellationToken) As Task

Remarks

This method will reset the component's properties to their default values.

ResolveRemoteHost Method (Ping Component)

Resolves the hostname in RemoteHost to an IP address.

Syntax

• C#
• VB.NET

public void ResolveRemoteHost();

Async Version
public async Task ResolveRemoteHost();
public async Task ResolveRemoteHost(CancellationToken cancellationToken);

Public Sub ResolveRemoteHost()

Async Version
Public Sub ResolveRemoteHost() As Task
Public Sub ResolveRemoteHost(cancellationToken As CancellationToken) As Task

Remarks

This method resolves the hostname specified by RemoteHost to an IP address. The resolved value is available in the RemoteHost property after this method returns.

In most cases calling this method is not necessary, the component will resolve the hostname automatically when necessary. If DelayHostResolution is true this method may be called to manually resolve RemoteHost if desired.

WakeOnLAN Method (Ping Component)

This method sends a Wake-On-LAN packet.

Syntax

• C#
• VB.NET

public void WakeOnLAN(string remoteHost, string MACAddress);

Async Version
public async Task WakeOnLAN(string remoteHost, string MACAddress);
public async Task WakeOnLAN(string remoteHost, string MACAddress, CancellationToken cancellationToken);

Public Sub WakeOnLAN(ByVal RemoteHost As String, ByVal MACAddress As String)

Async Version
Public Sub WakeOnLAN(ByVal RemoteHost As String, ByVal MACAddress As String) As Task
Public Sub WakeOnLAN(ByVal RemoteHost As String, ByVal MACAddress As String, cancellationToken As CancellationToken) As Task

Remarks

When this method is called, a Wake-On-LAN packet is sent to RemoteHost (which may also be a broadcast address). This has the effect of powering on the machine (if such functionality is supported by the network card on the remote machine).

The physical address of the remote host must be supplied in the MACAddress parameter.

Error Event (Ping Component)

Information about errors during data delivery.

Syntax

• C#
• VB.NET

public event OnErrorHandler OnError;

public delegate void OnErrorHandler(object sender, PingErrorEventArgs e);

public class PingErrorEventArgs : EventArgs {
  public int ErrorCode { get; }
  public string Description { get; }
}

Public Event OnError As OnErrorHandler

Public Delegate Sub OnErrorHandler(sender As Object, e As PingErrorEventArgs)

Public Class PingErrorEventArgs Inherits EventArgs
  Public ReadOnly Property ErrorCode As Integer
  Public ReadOnly Property Description As String
End Class

Remarks

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

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

Response Event (Ping Component)

This event is fired when a response packet is received.

Syntax

• C#
• VB.NET

public event OnResponseHandler OnResponse;

public delegate void OnResponseHandler(object sender, PingResponseEventArgs e);

public class PingResponseEventArgs : EventArgs {
  public int RequestId { get; }
  public string ResponseSource { get; }
  public string ResponseStatus { get; }
  public int ResponseTime { get; }
}

Public Event OnResponse As OnResponseHandler

Public Delegate Sub OnResponseHandler(sender As Object, e As PingResponseEventArgs)

Public Class PingResponseEventArgs Inherits EventArgs
  Public ReadOnly Property RequestId As Integer
  Public ReadOnly Property ResponseSource As String
  Public ReadOnly Property ResponseStatus As String
  Public ReadOnly Property ResponseTime As Integer
End Class

Remarks

The RequestId parameter is used along with the RequestId property to match requests with responses.

ResponseStatus is set to OK for normal operation, or it contains an error string, such as Network unreachable or Host unreachable.

Config Settings (Ping Component)

Ping Config Settings

ICMP Config Settings

Socket Config Settings

Base Config Settings

Trappable Errors (Ping Component)

Ping Errors

The component may also return one of the following error codes, which are inherited from other components.

ICMP Errors

SSL Errors

TCP/IP Errors