用户在Visual Studio C＃中绘制一条直线以及随着鼠标移动的直线？

Question

the user should be able to draw a straight line on a panel similar to drawing a straight line in paint .

the user clicks on the panel and when he moves the mouse the line should also move along with the mouse (ie similar to drawing a staright line in paint) and when the user releases the mouse the line should have been drawn from the original point of click to this release point .

ie not a free hand line.

is there any animation for this ?

Answer 1

How about this? :

public class LinePanel : Panel
{
    public LinePanel()
    {
        this.MouseDown += (src, e) => { LineStartPos = LineEndPos = e.Location; Capture = true; Invalidate(); };
        this.MouseMove += (src, e) => { if (Capture) { LineEndPos = e.Location; Invalidate(); } };
        this.MouseUp += (src, e) => { if (Capture) { LineEndPos = e.Location; } Capture = false; Invalidate(); };
    }

    private Point LineStartPos, LineEndPos;

    protected override void OnPaint(PaintEventArgs e)
    {
        base.OnPaint(e);

        if (LineStartPos != LineEndPos)
            e.Graphics.DrawLine(new Pen(Color.Black, 2), LineStartPos, LineEndPos);
    }
}

To test you can just add a new LinePanel() to the Controls collection of your form, and set location/size or anchor / dock paramaters to size it.