MDAC 2.5 SDK - ADO

Cancel Method Example (VB)

See Also

This example uses the Cancel method to cancel a command executing on a Connection object if the connection is busy.

Public Sub CancelX()

   Dim cnn1 As ADODB.Connection
   Dim strCnn As String
   Dim strCmdChange As String
   Dim strCmdRestore As String
   Dim booChanged As Boolean
   
   ' Open a connection.
   Set cnn1 = New ADODB.Connection
      strCnn = "Provider=sqloledb;" & _
      "Data Source=srv;Initial Catalog=Pubs;User Id=sa;Password=; "
   cnn1.Open strCnn
   
   ' Define command strings.
   strCmdChange = "UPDATE titles SET type = 'self_help' " & _
      "WHERE type = 'psychology'"
   strCmdRestore = "UPDATE titles SET type = 'psychology' " & _
      "WHERE type = 'self_help'"
   
   ' Begin a transaction, then execute a command asynchronously.
   cnn1.BeginTrans
   cnn1.Execute strCmdChange, , adAsyncExecute
   
   ' do something else for a little while – this could be changed
      For i = 1 To 10
         i = i + i
         Debug.Print i
      Next i

   ' If the command has NOT completed, cancel the execute
   ' and roll back the transaction. Otherwise, commit the
   ' transaction.
   If CBool(cnn1.State And adStateExecuting) Then
      cnn1.Cancel
      cnn1.RollbackTrans
      booChanged = False
      MsgBox "Update canceled."
   Else
      cnn1.CommitTrans
      booChanged = True
      MsgBox "Update complete."
   End If
   
   ' If the change was made, restore the data
   ' because this is a demonstration.
   If booChanged Then
      cnn1.Execute strCmdRestore
      MsgBox "Data restored."
   End If
      
   cnn1.Close
   
End Sub