[填空题] 下面程序是由鼠标事件在窗体上画图，如果按下鼠标将可以画图，双击窗体可以清除所画图形。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

[填空题] 下面程序是由鼠标事件在窗体上画图，如果按下鼠标将可以画图，双击窗体可以清除所画图形。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