用VB如何运行窗体时，鼠标只在窗体上活动，不能到电脑桌面上，如何作？

Private Declare Function ClipCursor Lib "user32" (lpRect As Any) As Long

Private Type rect
    sbleft As Long
    sbtop As Long
    sbright As Long
    sbbottom As Long
End Type



Private Sub Command1_Click()
'定位鼠标
       Dim x As Long, y As Long
       Dim newrect As rect
       x& = Screen.TwipsPerPixelX
       y& = Screen.TwipsPerPixelY
       With newrect
            .sbleft = Form1.Left / x
            .sbtop = Form1.Top / x
            .sbright = .sbleft + Form1.Width / x
            .sbbottom = .sbtop + Form1.Height / x
       End With
      
       ClipCursor newrect
End Sub