Sendmessage 没有引发点击事件

Question

我有这个 vb6 形式。

在后台桌面Winsta0\second_desktop中启动 这是其中的代码：

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Private Const WM_LBUTTONDOWN = &H201
Private Const WM_LBUTTONUP = &H202

Private Sub Command1_Click()
    Dim X As Long, Y As Long, lParam As Long, hwnd
    X = 150
    Y = 50
    hwnd = Me.hwnd
    lParam = MakeLParam(X, Y)
    SendMessage hwnd, WM_LBUTTONDOWN, 1, lParam
    SendMessage hwnd, WM_LBUTTONUP, 0, lParam
End Sub

Private Function lshft(num As Long, shifts As Byte) As Long
    lshft = num * (2 ^ shifts)
End Function

Private Function MakeLParam(ByVal LoWord As Long, ByVal HiWord As Long) As Long
        MakeLParam = lshft(HiWord, 16) Or (LoWord And &HFFFF)
End Function

Private Sub Form_Click()
    MsgBox "Clicked"
End Sub

Private Sub Form_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
    MsgBox "mouseup"
End Sub

如果我启动它并单击按钮，只会引发 Form_MouseUp 事件，但不会引发 Form_Click。我也尝试使用 Form_MouseDown 并且它也有效。

我怎样才能提高 Form_Click？ 也可以使用外部 C++ 进程的解决方案。

谢谢

Answer 1

我认为您正在寻找使用

PostMessage

功能而不是

SendMessage

。

PostMessage

函数向指定线程的消息队列中添加一条消息，并立即返回。这将允许系统处理消息队列并适当地引发点击事件。

这是一个如何使用

PostMessage

而不是

SendMessage

的例子：

Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

Private Sub Command1_Click()
    Dim X As Long, Y As Long, lParam As Long, hwnd
    X = 150
    Y = 50
    hwnd = Me.hwnd
    lParam = MakeLParam(X, Y)
    PostMessage hwnd, WM_LBUTTONDOWN, 1, lParam
    PostMessage hwnd, WM_LBUTTONUP, 0, lParam
End Sub

这应该会按预期触发

Form_Click

事件。