How do I draw a rectangle based on the movement of the mouse?

Question

I found sample code here for drawing on a form:

http://msdn.microsoft.com/en-us/library/aa287522(v=vs.71).aspx

As a followup to this requirement (discovering

Answer 1

ControlPaint.DrawReversibleFrame() will do what you want. Performance is not generally a problem - just keep it small and clean.

-- EDIT: Added a code sample. StackOverflowException indicates something is wrong - but without seeing yours, can't answer directly.

private Point? _start;
private Rectangle _previousBounds;

protected override void OnMouseDown(MouseEventArgs e)
{
    _start = e.Location;
    base.OnMouseDown(e);
}

protected override void OnMouseMove(MouseEventArgs e)
{
    if( _start.HasValue ) {
        ReverseFrame();
        DrawFrame(e.Location);
    }

    base.OnMouseMove(e);
}

protected override void OnMouseUp(MouseEventArgs e)
{
    ReverseFrame();
    _start = null;
    base.OnMouseUp(e);
}

private void ReverseFrame()
{
    ControlPaint.DrawReversibleFrame(_previousBounds, Color.Red, FrameStyle.Dashed);

}
private void DrawFrame(Point end)
{
    ReverseFrame();

    var size = new Size(end.X - _start.Value.X, end.Y - _start.Value.Y);
    _previousBounds = new Rectangle(_start.Value, size);
    _previousBounds = this.RectangleToScreen(_previousBounds);
    ControlPaint.DrawReversibleFrame(_previousBounds, Color.Red, FrameStyle.Dashed);
}