处理鼠标移出事件

王朝vb·作者佚名  2006-01-08
窄屏简体版  字體: |||超大  

Windows提供的鼠标移出消息有时候很有用,但是VB6中没有把这个事件封装给我们。

但是我们仍然可以使用子类化技术实现他,下面的代码就是一个简单的例子来处理Windows的

WM_MOUSELEAVE消息的,我演示的是鼠标移出一个Button时的情形。

1.加入一个模块,专门用来处理子类函数:

Option Explicit

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'Copyright 2002 40Star, All Rights Reserved.

'

'E-Mail :40Star@163.com

'Distribution:你可以完全自由随便的使用这段代码,不管你用于任何目的

' 程序在于交流和学习

' 如有任何BUG请和我联系

'

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Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _

(ByVal hwnd As Long, ByVal wMsg As Long, _

ByVal wParam As Long, lParam As String) As Long

Private 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

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

Const GWL_WNDPROC = (-4&)

Dim PrevWndProc&

Private Const WM_DESTROY = &H2

Public Declare Function TrackMouseEvent Lib "user32" (lpEventTrack As TRACKMOUSEEVENTTYPE) As Long

Public Const TME_CANCEL = &H80000000

Public Const TME_HOVER = &H1&

Public Const TME_LEAVE = &H2&

Public Const TME_NONCLIENT = &H10&

Public Const TME_QUERY = &H40000000

Private Const WM_MOUSELEAVE = &H2A3&

Public Type TRACKMOUSEEVENTTYPE

cbSize As Long

dwFlags As Long

hwndTrack As Long

dwHoverTime As Long

End Type

Public bTracking As Boolean

Dim evtTrack As TRACKMOUSEEVENTTYPE

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Private Function SubWndProc(ByVal hwnd As Long, ByVal Msg As Long, _

ByVal wParam As Long, ByVal lParam As Long) _

As Long

If Msg = WM_DESTROY Then Terminate (hwnd)

'处理鼠标移出消息

If Msg = WM_MOUSELEAVE Then

bTracking = False

Form1.Print "The mouse left the form!"

End If

SubWndProc = CallWindowProc(PrevWndProc, hwnd, Msg, wParam, lParam)

End Function

Public Sub Init(hwnd As Long)

PrevWndProc = SetWindowLong(hwnd, GWL_WNDPROC, AddressOf SubWndProc)

End Sub

Public Sub Terminate(hwnd As Long)

Call SetWindowLong(hwnd, GWL_WNDPROC, PrevWndProc)

End Sub

' -- 模块结束 -- '

2. 窗体中处理需要加入的代码:

Option Explicit

Private Sub Command1_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)

If bTracking = False Then

bTracking = True

Dim ET As TRACKMOUSEEVENTTYPE

'initialize structure

ET.cbSize = Len(ET)

ET.hwndTrack = Command1.hwnd

ET.dwFlags = TME_LEAVE

'start the tracking

TrackMouseEvent ET

End If

End Sub

Private Sub Form_Load()

Call Init(Command1.hwnd)

End Sub

Private Sub Form_Unload(Cancel As Integer)

Call Terminate(Command1.hwnd)

End Sub

此例程在Win2000 + VB6中调试通过

 
 
 
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