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鼠标画直线

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鼠标画直线

发表于：2007-06-19 14:50:28 楼主

我想用vb.net写一个画直线的类
imports system.drawing
imports system.drawing.drawing2d
public class form1
dim startpoint as point
dim endpoint as point
dim ismousedown as boolean = false
private sub pctbox_mousedown（byval sender as object, byval e as system.windows.forms.mouseeventargs) handles pctbox.mousedown
ismousedown = true
startpoint.x = e.x
startpoint.y = e.y
end sub
private sub pctbox_mousemove（byval sender as object, byval e as system.windows.forms.mouseeventargs) handles pctbox.mousemove
dim bmp as new bitmap（pctbox.clientsize.width, pctbox.clientsize.height)
if ismousedown then
endpoint.x = e.x
endpoint.y = e.y
dim mygraphics as graphics = graphics.fromimage（bmp)
mygraphics.drawline（pens.black, startpoint, endpoint)
pctbox.image = bmp
end if
end sub
private sub pctbox_mouseup（byval sender as object, byval e as system.windows.forms.mouseeventargs) handles pctbox.mouseup
ismousedown = false
end sub
end class

但是这个只能画一条，当画另一条时，第一条就删掉了
怎么才能画多条？？？
在线等待中
注：pctbox是picturebox控件

发表于：2007-06-19 15:38:481楼得分:0

这个问题出现在你触发 pctbox_mousemove时，每次都会对 bitmap来一次new当然不会有２条线

发表于：2007-06-19 15:47:122楼得分:0

你试一下这个：我刚刚改的：

imports system.drawing
imports system.drawing.drawing2d
public class form1
dim _graphicpic as graphics
dim startpoint as point
dim endpoint as point
dim ismousedown as boolean = false
private sub pctbox_mousedown（byval sender as object, byval e as system.windows.forms.mouseeventargs) handles pctbox.mousedown
ismousedown = true
startpoint.x = e.x
startpoint.y = e.y
end sub
private sub pctbox_mousemove（byval sender as object, byval e as system.windows.forms.mouseeventargs) handles pctbox.mousemove

if ismousedown then
endpoint.x = e.x
endpoint.y = e.y

end if
end sub
private sub pctbox_mouseup（byval sender as object, byval e as system.windows.forms.mouseeventargs) handles pctbox.mouseup
_graphicpic.drawline（pens.black, startpoint, endpoint)
ismousedown = false
end sub

private sub pctbox_paint（byval sender as object, byval e as system.windows.forms.painteventargs) handles pctbox.paint

end sub

private sub form1_load（byval sender as object, byval e as system.eventargs) handles me.load
_graphicpic = pctbox.creategraphics（)
end sub
end class

发表于：2007-06-19 15:47:503楼得分:0

是不是你想要的效果？

发表于：2007-06-19 19:06:464楼得分:0

虽然能够同时画几条直线
但是看不出动态的效果
我是想在鼠标移动的过程中能够看得直线？？？
有没有更好的方法啊～
谢谢了！

发表于：2007-06-20 08:25:365楼得分:0

去我的博客看看，有源码的

http://blog.csdn.net/wzuomin/archive/2006/12/13/1441007.aspx

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