查看完整版本: 如何拦截ComboBox的mouse右键

如何拦截ComboBox的mouse右键

如何拦截ComboBox的mouse右键

作者: 王国荣　

在ComboBox上按右键时，会有一个popup menu出现，如何令之不出现呢？
在editBox中可用Subclassing的技巧check msg是否是WM_RBUTTONDOWN 来拦截mouse
是否按了右键而後吃掉该message(不Call CallWindowProc())，而使之不会出现
popup menu。但在ComboBox中，按了mouse右键，却仍出现Popup Menu，
查了一下按右键时，发现是 WM_PARENTNOTIFY的讯息，而不是
wm_rbuttondown， 这该如何才能使之不出现Popup menu

这是个有趣的问题，ComboBox 是由 "Edit"(TextBox 的前身) 及 "ListBox"
两种 Windows 的 control 所组成的，而在 ComboBox 上面按下滑鼠右钮是由
"Edit" 来处理，因此拦截的方法是：

  1. 呼叫 EnumChildWindows 取得 ComboBox 的 "Edit" 子视窗的 hWnd
  2. 拦截 "Edit" hWnd。

而取得ListBox的hWnd请叁考改变“ComboBox中ListBox的宽度”

注释：以下程式在form
Option Explicit
** hwnd5 As Long

** Sub Form_Load()
Dim ret As Long
注释：取得Combo内EditBox的hwnd
hwnd5 = FindEditInCombo(Combo1)
注释：记录原本的Window Procedure的位址
preWinProc = GetWindowLong(hwnd5, GWL_WNDPROC)
注释：设定EditBox的window Procedure到wndproc
ret = SetWindowLong(hwnd5, GWL_WNDPROC, AddressOf wndproc)
End Sub

** Sub Form_Unload(Cancel As Integer)
Dim ret As Long
注释：取消Message的截取，而使之又只送往原来的Window Procedure
ret = SetWindowLong(hwnd5, GWL_WNDPROC, preWinProc)
End Sub

注释：以下程式在.bas module
Option Explicit

Declare Function EnumChildWindows Lib "user32" _
   (ByVal hWndParent As Long, ByVal lpEnumFunc As Long, _
   ByVal lParam As Long) As Long
Declare Function GetClassName Lib "user32" Alias "GetClassNameA" _
       (ByVal hwnd As Long, ByVal lpClassName As String, _
        ByVal nMaxCount As Long) As Long
Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" _
  (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" _
  (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" _
  (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, ByVal Msg As Long, _
   ByVal wParam As Long, ByVal lParam As Long) As Long

Public Const GWL_WNDPROC = (-4)
Public Const WM_MOUSEMOVE =