how to use drag and drop function?

Question

me and my frens are doing a project on a knapsack based game.
so we need to use drag and drop function to do a particular task.
so can anybody help us in using an function of drag and drop,like simply creating and object and drag that object in the form using mouse.

Answer 1

Hi,

You can develop your own custom control for this property.

You need to be similar with OnPaint,MouseDown,MouseUp and MouseMove events.

Here is a sample that draws a line on the form and allows user to move it at runtime.

    public class MyLine:Control
    {

        bool drawBold = false;
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            Pen p = null;
            if (drawBold)
            {
               p= new Pen(this.ForeColor, this.Height);
            }
            else
            {
               p= new Pen(this.ForeColor, this.Height-5);
            }
            e.Graphics.DrawLine(p , 0, this.Height/2, this.Width, this.Height/2);
        }

        protected override void OnMouseHover(EventArgs e)
        {
            base.OnMouseHover(e);
            drawBold = true;
            this.Refresh();
        }
        protected override void OnMouseLeave(EventArgs e)
        {
            base.OnMouseLeave(e);
            drawBold = false;
            this.Refresh();
        }

        //to move control
        Point p = new Point();
        protected override void OnMouseDown(MouseEventArgs e)
        {
            base.OnMouseDown(e);
            p.X = e.X;
            p.Y = e.Y;

        }
        protected override void OnMouseMove(MouseEventArgs e)
        {
            base.OnMouseMove(e);
            if (e.Button == MouseButtons.Left)
            {
                this.Location = new Point(e.X - p.X + this.Location.X, e.Y - p.Y + this.Location.Y);

            }
        }
    }