绘制直线的问题
怎么写能象   “附件”-“画图”   里面的“画直线”那样效果。
总是乱跑。谢谢了。

------解决方案--------------------
是WebForm还是WinForm的？
WebForm的话用VML+js
WinForm的话用GDI就行了。
------解决方案--------------------
我和VS2005做了一个画线的，楼主有兴趣可以参考一下：

public partial class DrawLine : Form
{
class LineObj
{
private Point m_start;
private Point m_end;
public LineObj(Point start, Point end)
{
this.m_start = start;
this.m_end = end;
}
public void Draw(Graphics g, Pen pen)
{
g.DrawLine(pen, m_start, m_end);
}
}

private Point m_startPoint = Point.Empty;

List <LineObj> lineList = new List <LineObj> ();
public DrawLine()
{
InitializeComponent();
this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.OptimizedDoubleBuffer, true);
}
private void drawLine(Graphics g, Point startPoint, Point endPoint)
{
BufferedGraphicsContext context = BufferedGraphicsManager.Current;
BufferedGraphics bg = context.Allocate(g, this.ClientRectangle);
bg.Graphics.Clear(this.BackColor);
foreach (LineObj line in this.lineList)
{
line.Draw(bg.Graphics, SystemPens.ControlText);
}
bg.Graphics.DrawLine(SystemPens.ControlText, startPoint, endPoint);
bg.Render();
bg.Dispose();
bg = null;
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
foreach (LineObj line in this.lineList)
{
line.Draw(e.Graphics, SystemPens.ControlText);
}
}
protected override void OnMouseDown(MouseEventArgs e)
{
base.OnMouseDown(e);
this.m_startPoint = new Point(e.X, e.Y);
}
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
if (e.Button == MouseButtons.Left)
{
this.drawLine(this.CreateGraphics(), this.m_startPoint, new Point(e.X, e.Y));
}
}
protected override void OnMouseUp(MouseEventArgs e)
{
base.OnMouseUp(e);
LineObj line = new LineObj(this.m_startPoint, e.Location);
this.lineList.Add(line);
}
}

------解决方案--------------------
http://topic.csdn.net/t/20030107/09/1333570.html