float MeasureString(string stringToPaint, string fontName, int fontSize) {

 Font font = new Font(fontName, fontSize, FontStyle.Regular);

 // Set TextFormatFlags to no padding so strings are drawn together.
 TextFormatFlags flags = TextFormatFlags.NoPadding | 
TextFormatFlags.NoPrefix;

 // Declare a proposed size with dimensions set to the maximum integer 
value.
 Size proposedSize = new Size(int.MaxValue, int.MaxValue);

 Size size = TextRenderer.MeasureText( stringToPaint,
       font, proposedSize, flags);
 return size.Width;
}