如何在VB例程中接收自定义消息

日期：2007年6月7日作者：相关tags: 何在 VB 例程接收自定义消息

　　Option EXPlicit
　　　Private Const GWL_WNDPROC = -4
　　　Public Const GWL_USERDATA = (-21)
　　　Public Const WM_SIZE = &H5
　　　Public Const WM_USER = &H400
　　　Private 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 Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" _
　　　(ByVal hwnd As Long, ByVal nIndex As Long) As Long
　　Private Declare Function SetWindowLong Lib "user32" Alias _
　　　"SetWindowLongA" (ByVal hwnd As Long, _
　　　　ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
　　Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
　　Public Function Hook(ByVal hwnd As Long) As Long
　　　Dim pOld As Long
　　‘指定自定义的窗口过程
　　　pOld = SetWindowLong(hwnd, GWL_WNDPROC, _
　　　AddressOf WindowProc)
　　‘保存原来默认的窗口过程指针
　　　SetWindowLong hwnd, GWL_USERDATA, pOld
　　　Hook = pOld
　　End Function

　　Public Sub Unhook(ByVal hwnd As Long, ByVal lpWndProc As Long)
　　　Dim temp As Long
　　　注释：Cease subclassing.
　　　temp = SetWindowLong(hwnd, GWL_WNDPROC, lpWndProc)
　　End Sub

　　Function WindowProc(ByVal hw As Long, ByVal uMsg As Long, _
　　　ByVal wParam As Long, ByVal lParam As Long) As Long
　　　If uMsg = WM_SIZE Then
　　　‘处理WM_SIZE消息
　　　　MsgBox "SIZE"
　　　End If
　　　If uMsg = WM_USER + 1 Then
　　　　MsgBox wParam
　　　End If
　　　Dim lpPrevWndProc As Long
　　‘查询原来默认的窗口过程指针
　　　lpPrevWndProc = GetWindowLong(hw, GWL_USERDATA)
　　‘调用原来的窗口过程
　　　WindowProc = CallWindowProc(lpPrevWndProc, hw, uMsg,wParam, lParam)
　　End Function