下面程序是由鼠标事件在窗体上画图，如果按下鼠标可以画图，双击窗体则可以清除所画图形。补充完整下面的程序。首先在窗体层定义如下变量：

Dim PaintStart As Boolean

编写如下事件过程：

Private Sub Form_Load()

DrawWidth=2

ForeColor=vbGreen

End Sub

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

PaintStart=True

End Sub

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

If PaintStart Then

PSet(X，Y)

End If

End Sub

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

End Sub

Private Sub Form_DblClick()

Cls

End Sub