鼠标编程小技巧二则

作者：土人
一.通过鼠标在屏幕上的移动来控件程序界面

本例通过鼠标在屏幕上的移动来控制程序窗体的显示与隐藏：当鼠标移动到窗体所在区域时窗体显示，反之隐藏起来。仅需一条API函数：GetCursorPos。注意：如果需要将API函数置于模块中请对代码作相应修改。要尝试本例，需给标准EXE工程缺省添加一个Timer控件。

Private Type POINTAPI
x As Long
y As Long
End Type

Private Declare Function GetCursorPos Lib "user32" (lpPoint As POINTAPI) As Long

Private Sub Form_Load()
Me.Visible = False
Timer1.Enabled = True
Timer1.Interval = 100
End Sub

Private Sub Timer1_Timer()
Dim lResult As Long
Dim lpPoint As POINTAPI
Dim iCounter As Integer
lResult = GetCursorPos(lpPoint)
If lpPoint.x < Me.Left \ Screen.TwipsPerPixelX Or lpPoint.x > (Me.Left + _
Me.Width) \ Screen.TwipsPerPixelX Or lpPoint.y < Me.Top \ _
Screen.TwipsPerPixelY Or lpPoint.y - 10 > (Me.Top + Me.Height) \ _
Screen.TwipsPerPixelY Then
Me.Visible = False ''鼠标在窗体区域之外时
Else
Me.Visible = True ''鼠标在窗体区域之内时
End If
End Sub

二.获得Mouse_Exit事件

所谓Mouse_Exit事件，是指鼠标指针离开某一控件所应发生的事件。本例是通过Form_MouseMove事件来判断鼠标指针是在窗体之内还是窗体之外的，你可根据需要作相应改动。请给窗体缺省创建一个按钮(用于观察效果)。

Private Declare Function SetCapture Lib "user32" (ByVal hWnd As Long) As Long
Private Declare Function ReleaseCapture Lib "user32" () As Long

Private Sub Form_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
Dim MouseExit As Boolean
MouseExit = (0 <= X) And (X <= Me.Width) And (0 <= Y) And (Y <= Me.Height)
If MouseExit Then
Me.Caption = "鼠标指针在窗体范围内"
Command1.Enabled = True
SetCapture Me.hWnd
Else
Me.Caption = "鼠标指针在窗体范围外"
Command1.Enabled = False
ReleaseCapture
End If
End Sub