Add comma to numbers every three digits using C#
<p>I want to add comma to decimal numbers every 3 digits using c#.<br>
I wrote this code :</p>

<pre><code>double a = 0; 
a = 1.5;
Interaction.MsgBox(string.Format("{0:#,###0}", a));
</code></pre>

<p>But it returns 2.<br>
Where am I wrong ?<br>
Please describe how can I fix it ?</p>

<hr>

<p><strong>All answers was useful , unfortunately I don't know to mark which answer as answer,<br>
Thank you for all teachers.</strong></p>
