According to MSDN, it is not a particularly good idea to use classes within the System.Drawing namespace in a Windows Service or ASP.NET Service. Now I am d
You could use TextRenderer instead. I know it's weird to use something from System.Windows.Forms in ASP.NET, but it doesn't appear to have the same warning about not being supported in ASP.NET. I have used both TextRenderer and Graphics.MeasureString to measure strings in ASP.NET applications, so they both work. I had never seen the warning about System.Drawing not being advisable in ASP.NET.
TextRenderer is a lot slower than Graphics.MeasureString, FWIW.