Dragable rectangles

Hello.

I have a question..

I have this script:

Code:

        int mouseDownX;
        int mouseDownY;

        int width;
        int height;

        private void Form1_MouseUp(object sender, MouseEventArgs mouseEv)
        {
            width = mouseEv.X - mouseDownX;
            height = mouseEv.Y - mouseDownY;

            textBox2.Text = Convert.ToString(mouseEv.Location);

            Graphics graphics = this.CreateGraphics();

            Rectangle rectangle = new Rectangle(
                    mouseDownX, mouseDownY, width, height);

            graphics.DrawRectangle(Pens.Red, rectangle);
        }

        private void Form1_MouseDown(object sender, MouseEventArgs mouseEv)
        {
            textBox1.Text = Convert.ToString(mouseEv.Location);

            mouseDownX = mouseEv.X;
            mouseDownY = mouseEv.Y;
        }

Which works fine if I make a rectangle from the left top corner to the right bottom corner

But is there any easier way of just making rectangles?

Here is a video of what I want:
http://www.youtube.com/watch?v=V5YO4U1UnO0

And here is a download link to my project:
http://peecee.dk/upload/download/123329

So I want to be able to draw rectangles from any angle if you understand?