还是：如果高手就请回答！

[gulfel]

橡皮筋是什么意思？用什么函数或命令？是不是很弱智的问题？也是很容易得分吧？请回答，给高分

[tipstudio_zsp]

橡皮筋是一种效果

参看下例

---- 以下我们通过一个示例来完整实现绘图控件中的大十字光标，还演示如何实现用“橡皮筋”效果来画矩形：

---- 在VB中新建一个标准EXE工程，在Form1中加入一个Picture控件，其Name设为PicDraw，可以装入一个图象文件，PicDraw的大小和其中的图象大小基本上覆盖大部分的Form1即可。实现代码如下所示。此程序在VB5.0中运行通过。

Option Explicit
Private Old_X As Single
Private Old_Y As Single
Private isMouseDown As Boolean
Private Box_X0 As Single
Private Box_Y0 As Single
Private Box_X1 As Single
Private Box_Y1 As Single
Private PenColor As Long
Private CrossColor As Long

Private Sub Form_Load()
CrossColor = QBColor(8)
PenColor = QBColor(15)
picDraw.DrawMode = vbXorPen
picDraw.MouseIcon = LoadPicture
(App.Path & "\no.cur")
picDraw.MousePointer = vbCustom
isMouseDown = False
Box_X0 = Box_X1 = Box_Y0 = Box_Y1 = 0
End Sub

Private Sub picDraw_MouseDown
(Button As Integer,
Shift As Integer, X As Single, Y As Single)
If isMouseDown = True Then
'先前已经用鼠标定义了一个点
Box_X1 = X
Box_Y1 = Y
isMouseDown = False
picDraw.DrawMode = vbCopyPen
picDraw.Line (Box_X0, Box_Y0)-
(Box_X1, Box_Y1),
PenColor, B
picDraw.DrawMode = vbXorPen
'画一个光标
picDraw.Line (0, Y)-(picDraw.ScaleWidth, Y),
CrossColor
picDraw.Line (X, 0)-(X, picDraw.ScaleHeight),
CrossColor
Old_X = X
Old_Y = Y
Else
'定义了一个矩形的第一个顶点，则擦除光标
picDraw.Line (0, Y)-(picDraw.ScaleWidth, Y),
CrossColor
picDraw.Line (X, 0)-(X, picDraw.ScaleHeight),
CrossColor
Box_X0 = X
Box_Y0 = Y
isMouseDown = True
End If
End Sub

Private Sub picDraw_MouseMove(Button As Integer,
Shift As Integer, X As Single, Y As Single)
If isMouseDown = True Then
'拖动鼠标来定义矩形的另外一个顶点，
此时擦除前一个矩形，绘制新的矩形
picDraw.Line (Box_X0, Box_Y0)-(Old_X, Old_Y),
PenColor, B
picDraw.Line (Box_X0, Box_Y0)-(X, Y), PenColor, B
Else
'消除旧光标线
picDraw.Line (0, Old_Y)-(picDraw.ScaleWidth, Old_Y),
CrossColor
picDraw.Line (Old_X, 0)-(Old_X, picDraw.ScaleHeight),
CrossColor
'画新的光标线
picDraw.Line (0, Y)-(picDraw.ScaleWidth, Y),
CrossColor
picDraw.Line (X, 0)-(X, picDraw.ScaleHeight),
CrossColor
End If
Old_X = X
Old_Y = Y
End Sub

[sonicdater]

学习.