Creating your own cool Volume Control using GDI+

private void VolumeControl_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
{
if (MovingDial)
{
// get mouse position
double xpos = (double)e.X;
double ypos = (double)e.Y;
// calculate the center of the dial
double xcenter = ClientRectangle.Width/2;
double ycenter = ClientRectangle.Width/2;
// subtract the center from the actual position to get the relative position to the midpoint
xpos -= xcenter;
ypos -= ycenter;
// now we can calculate the angle using the arctangent function. this arctangent function
// is nice because it takes the sign of x and y into account when figuring the angle
double angle = Math.Atan2(ypos, xpos);
// Set the property to the new angle
TheOffset = angle;
// Set the red dot position
TheDotPosition = TheOffset;
// Get the old volume to use to see if its been changed
int OldVolume = TheVolume;
// Calculate the the volume (number from 1-10) using the angle of the offset of the dial from
// its initial position
CalcVolume(TheOffset);
// if the old volume doesn't equal the new volume, then fire a VolumeChanged Event
if (OldVolume != TheVolume)
{
VolumeChanged(this, e);
}
// force the dial to redraw with the new position
Invalidate();
}
}

private void volumeControl1_VolumeChanged(object sender, System.EventArgs e)
{
label1.Text = volumeControl1.Volume.ToString();
}

this.volumeControl1.VolumeChanged += new VolumeControl.VolumeControl.VolumeChangedEventHandler this.volumeControl1_VolumeChanged);