Add comma to numbers every three digits using C#

Question

I want to add comma to decimal numbers every 3 digits using c#.
I wrote this code :

double a = 0; 
a = 1.5;
Interaction.MsgBox(string.Format(\"{0:#,###0}         


        

Answer 1

Here is how to do it:

 string.Format("{0:0,0.0}", a)