Using Connection Object Events

The Connection object supports a number of events that allow your application to execute custom code. These events are associated with connecting to a data source, executing SQL commands, and managing transactions at the connection level.

The following table describes the events associated with the Connection Object.

Event	Description
AbortTransaction	Fires after the RollbackTrans method is called.
BeginTransaction	Fires after the BeginTrans method is called.
CommitTransaction	Fires after the CommitTrans method is called.
ConnectComplete	Fires when a connection attempt has completed successfully, failed, or timed out.
Disconnect	Fires when an active connection is closed.
ExecuteComplete	Fires after the Execute method is called.
InfoMessage	Fires when a message is returned from OLE DB or the data source.
WillConnect	Fires after the Open method is called, but before the connection is established.
WillExecute	Fires after the Execute method is called, but before the command is completed.

Enabling ADO Events

When you declare an ADO object, you can use the WithEvents keyword to expose the object's events to your application. If you declare a Connection object with its events exposed, the Connection object appears in the Visual Basic Object box list and all the available events for the object appear in the Procedures/Events box list.

The following example code declares a Connection object and exposes its events:

Public WithEvents cnStateUBookstore As Connection

You can now use the Connection object to execute statements or create Command objects or Recordset objects.

Adding Code to Connection Object Events

When you declare a Connection object using the WithEvents keyword, code is added to any of its associated events. The following example code displays a message box to the user when a connection attempt has successfully completed:

Sub cnStateUBookstore_ConnectComplete(ByVal pError As ADODB.Error, _
    adStatus As ADODB.EventStatusEnum, _
    ByVal pConnection As ADODB.Connection)

    If adStatus = adStatusOK Then
        MsgBox "The connection has been established with the data source."
    End If

End Sub

Note There are additional values that can be returned in the EventStatusEnum object.