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)  【13】  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)    【14】  End Sub Private Sub Form_Db1Click()    【15】  End Sub

【参考答案】

【13】PaintStart=True