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

Its doing it right. #,##0 means write at least one digit and zero decimals and space digit groups with comas. Therefore it rounds 1.5 to 2 as it cant write decimals. Try #,##0.00 instead. You'll get 1.50