Question

I try to change font size in runtime as following code, but I always get StackOverflowException.

protected override void OnResize(EventArgs e)
{
    this.bitmapDoubleBuffer = new Bitmap(base.Width, base.Height);
    this.backGraphics = Graphics.FromImage(this.bitmapDoubleBuffer);
}

public void ReDrawRuntime()
{
    SizeF sizeF = this.backGraphics.MeasureString(this.Text, this.Font);
    if (sizeF.Width > this.Size.Width)
    {
        this.Font = new Font(this.Font.Name, 20, this.Font.Style);
        sizeF = this.backGraphics.MeasureString(this.Text, this.Font);
    }
    this.backGraphics.DrawString(this.Text, 
                this.Font, 
                this.solidBrushForeColor, 
                (float)((int)width), 
                (float)((int)height));
    this.graphicsDoubleBuffer.DrawImage(this.bitmapDoubleBuffer, 0, 0);
 }

Answer 1

Cause changing font size wil increase the size of the control the text drwn on, which will riase Resize event agin (look on this.Font =.., this !!) , which will run your code again, which probabbly (according to the exception) will validate to true:

if (sizeF.Width > this.Size.Width)

condition again and so on…

So general rule is: do not change shape of the control inside OnResize, do it in another place.