可以進壹步限制，使鼠標不能碰到窗體邊界，試試如下代碼：
'倆command
Private Declare Sub ClipCursor Lib "user32" (lpRect As Any)
Private Declare Sub GetClientRect Lib "user32" (ByVal hWnd As Long, lpRect As RECT)
Private Declare Sub ClientToScreen Lib "user32" (ByVal hWnd As Long, lpPoint As POINT)
Private Declare Sub OffsetRect Lib "user32" (lpRect As RECT, ByVal x As Long, ByVal y As Long)
Private Type RECT
left As Long
top As Long
right As Long
bottom As Long
End Type
Private Type POINT
x As Long
y As Long
End Type
Private Sub Command1_Click() '限制鼠標
Dim client As RECT
Dim upperleft As POINT
GetClientRect Me.hWnd, client
upperleft.x = client.left
upperleft.y = client.top
ClientToScreen Me.hWnd, upperleft
OffsetRect client, upperleft.x, upperleft.y
ClipCursor client
End Sub
Private Sub Command2_Click() '取消限制
ClipCursor ByVal 0&
End Sub
Private Sub Form_Unload(Cancel As Integer) '釋放
ClipCursor ByVal 0&
End Sub