VB为自己的程序设定消息(可接收处理)

Private Sub Command1_Click()
Dim wParam As Long
Dim lParam As Long
Dim lResult As Long
　wParam = 12345
　lResult = SendMessage(Me.hwnd,WM_USER + 1 ,wParam,lParam)
End Sub

Private Sub Form_Load()
　Me.Tag = Hook(Me.hwnd)
End Sub

Private Sub Form_Unload(Cancel As Integer )
　Unhook Me.hwnd,Me.Tag
End Sub

Option Explicit

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 ,lParam As Any) As Long

Private Const GWL_WNDPROC = - 4
Public Const GWL_USERDATA = (- 21 )
Public Const WM_SIZE = &H5
Public Const WM_USER = &H400

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,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 "收到消息 WM_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,lParam)
End Function