Connected Property

Triggers a connection or disconnection.

Syntax

• C++
• Objective-C
• C

ANSI (Cross Platform)
int GetConnected();
int SetConnected(int bConnected);

Unicode (Windows)
BOOL GetConnected();
INT SetConnected(BOOL bConnected);

@property (nonatomic,readwrite,assign,getter=connected,setter=setConnected:) BOOL connected;
- (BOOL)connected;
- (void)setConnected:(BOOL)newConnected;

#define PID_MQTT_CONNECTED 3

IPWORKSIOT_EXTERNAL void* IPWORKSIOT_CALL IPWorksIoT_MQTT_Get(void *lpObj, int propid, int arridx, int *lpcbVal, int64 *lpllVal);
IPWORKSIOT_EXTERNAL int IPWORKSIOT_CALL IPWorksIoT_MQTT_Set(void *lpObj, int propid, int arridx, const void *val, int cbVal);

Default Value

FALSE

Remarks

This property triggers a connection or disconnection. Setting this property to True makes the class attempt to connect to the host identified by the RemoteHost property. If successful, after the connection is achieved the value of the property changes to True and the Connected event is fired.

Setting this property to False closes the connection.

By default the class will connect in plaintext. To enable SSL set SSLEnabled to True.

In addition, WebSocket connections are supported. To connect using WebSockets specify a hostname beginning with ws:// (plaintext) or wss:// (SSL). For instance, ws://test.mosquitto.org.

When connecting to an MQTT server, the class sends the following information:

• The values of the ClientId, CleanSession, and KeepAliveInterval properties.
• The value of the User property (if non-empty).
• The value of the Password property (if non-empty).
• The values of the WillTopic and WillMessage properties and the WillQOS and WillRetain configuration settings.
• MQTT 5 specific values from ClientTopicAliasMax, SessionExpInterval, ConnectProperties and WillProperties.

If CleanSession is True, check the SessionPresent configuration setting once connected to determine whether the server actually had any session state saved.

Refer to CleanSession, SaveSession, and RestoreSession for more information about MQTT sessions and session state persistence; refer to WillTopic, WillMessage, WillQOS, and WillRetain for more information about MQTT Wills.

Basic Connection Example

mqtt1.ClientId = "testClient";
mqtt1.CleanSession = true;
mqtt1.KeepAliveInterval = 30;
mqtt1.WillTopic = "wills/" + mqtt1.ClientId;
mqtt1.WillMessage = mqtt1.ClientId + " was disconnected ungracefully!";
mqtt1.Connect("mqtt.test-server.com", 1883);

This property is not available at design time.

Data Type

Boolean