I wanted to do something similar, but on a form with a background image, I found that when the text in the label changed the repaints were obvious with this method, so I did the following:
* Set the label AutoSize to true and TextAlign to MiddleCenter
Then, each time the text changed (mine was done using a timer) I called the following method:
private Point GetPosition()
{
int y = (this.Height / 2) - (label1.Height / 2);
int x = (this.Width / 2) - (label1.Width / 2);
return new Point(x, y);
}
And set the label's Location property to this return value. This ensured that the label was always in the center of the form when the text changed and the repaints for a full-screen form weren't obvious.