Private Declare Function SendMessage
Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg
As Long, ByVal wParam As Long, lParam As Any) As Long Private
Const EM_CANUNDO = &HC6 Private Const EM_UNDO =
&HC7
Private Sub Command1_Click() Dim i As
Integer i = SendMessage(Text1.hwnd, EM_UNDO, 0, 0) End
Sub
Private Sub Command2_Click() End End
Sub 在这个程序中,我们向文本框发送了一个EM_UNDO消息,该消息的功能是取消文本框的最后一个编辑操作。对于该消息,wParam和1Param均无用,故都设为0。