Movable Freeform/Round Edged Window/Form in C#

Introduction

It is a bit tricky in Visual Studio to create a movable free form window (irrespective of the language you choose). Here I am going to show you how easy it is.

Step 1

Create a form in C# and add one exit button too.

Step 2

Change the properties of the form like this. Change the Form Border Style as none and Transparence key to ‘control’.

Step 3

Add a picture box and a picture to the form.

Step 4

Now the final and the tricky part comes into the picture. Create the following mouse events for the newly created form.

public int diff_x;
public int diff_y;
public bool mouse_down = false;

private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
    diff_x = Form.MousePosition.X - Form.ActiveForm.Location.X;
    diff_y = Form.MousePosition.Y - Form.ActiveForm.Location.Y;
    mouse_down = true;
}

In the picture box’s mouse down event, we find out the difference in mouse positions and set a public variable mouse_down to true.

private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
    if (mouse_down == true)
    {
        Point p = new Point(MousePosition.X - diff_x, MousePosition.Y - diff_y);
        Form.ActiveForm.Location = p;
    }
}

In the mouse move event of the picture box, find out the position and set the active window to it. But we need to check whether the mouse is actually down or not. Only if the mouse is down, we need to look further for mouse movements.

private void pictureBox1_MouseUp(object sender, MouseEventArgs e) 
{
    mouse_down = false;
}

And here is the code for mouse up event. We are just changing the global variable mouse_down to false.

Add the following code to your exit button. Otherwise, you will face difficulty in closing your application.

private void button1_Click(object sender, EventArgs e)
{
    Dispose();
    this.Close();
}

Finally here is our movable transparent window in action!

History

• 11^th March, 2009: Initial post