确定鼠标钩子何时处理最后一条消息

Question

我有一个表单，其作用类似于下拉菜单，我显示非模式。我将鼠标挂钩附加到表单上，以确定何时从其中单击鼠标，以便我知道通过设置 Visible = False 来关闭它。

因为我希望 HookProc 处理最后一次单击，所以在确定事件处理程序已返回到 HookProc 之前，我无法处置 Hook 或 Dropdown。

这有点难以解释，但我希望下面的代码能让它更清楚一点：-

//Loop to display the dropdown.
Dim dd as New DropDown
dd.Visible = True
Do While dd.Visible
    Application.DoEvents()
    NativeMethods.MsgWaitForMultipleObjectsEx(0, IntPtr.Zero, 250, &HFF, 4)
Loop
// I want to dispose dd now, but how can I be sure that e.Handled (See below)
// has been returned to HookProc?

//A handler within dropdown to determine what to do with the mouse click.
Private Sub DropDown_MouseHookClick(ByVal sender As Object, ByVal e As MouseClickEventArgs)
    If IWantToCloseTheDropDown Then
        e.Handled = True
        MyHook.UnHook
        Me.Visible = False
    End If
    // All done, e.Handled is returned to HookProc.
    // But which happens first? Will e.Handled arrive at HookProc first, or will
    // the form display loop, above, notice that Visible is now False?
End Sub

//The main part of the hooking class.
Public Function MouseHookProc(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer
    Dim MyMouseHookStruct As MouseHookStruct = DirectCast(Marshal.PtrToStructure(lParam, GetType(MouseHookStruct)), MouseHookStruct)
    If nCode < 0 Then
        Return CallNextHookEx(hHook, nCode, wParam, lParam)
    Else
        Dim handle As Integer = MyMouseHookStruct.hwnd
        Dim c As Control = Control.FromHandle(New IntPtr(handle))
        If MouseUpOrDown Then
            Dim e As MouseHookClickEventArgs
            OnMouseClick(e)
            If e.Handled Then
                Return 1
            EndIf
        End If
        Return CallNextHookEx(hHook, nCode, wParam, lParam)
    End If
End Function

Answer 1

为什么不直接处理焦点事件呢？ Form_LostFocus 会告诉您他们何时聚焦于另一个控件/表单。那时您可以隐藏您的表单。

鼠标钩子对于检测您的表单是否具有焦点似乎有点过分了。

Answer 2

您正在绕过 .NET 机制来处理 Windows 事件

您不应该需要任何本机来处理 WinForms。此外，整个代码都会被垃圾收集，因此您do不必担心删除挂钩，

您可能需要查看form.deactivate 事件