C# Correctly Get String Width in Pixel

Hi everyone,
I'm developing new software for me. But I have a little problem. When I wanna get the String Width, already I use that code;

float aa = pe.Graphics.MeasureString("PROGRAMMING", Font).Width;

But this value is not correct. When I test that line with that code;

pe.Graphics.DrawString("PROGRAMMING", Font, Brushes.White, new PointF(0, 0));
float aa = pe.Graphics.MeasureString("PROGRAMMING", Font).Width;
pe.Graphics.DrawLine(new Pen(Brushes.CadetBlue, 4), new PointF(0, 1), new PointF(aa, 1));

Result of this code;
https://social.msdn.microsoft.com/Forums/getfile/573128[^]

The Line length always going wrong.
How can I solve this problem? That's calculate very important for my project. I'm waiting for your helps. Thanks for all answer. Have a good day...

Tags: C#, GDI, GDI+, Graphics, General Programming, Text