title: How to make validation for a textbox that accepts only comma(,) & digit in an ASP.NET application?
body: <p>I am working on a website. I am using C# corresponding to Visual Studio 2008. I want to make a text box that accept only numbers &amp; comma(,).
  For example, </p>
  
  <pre><code>-919981424199,78848817711,47171111747 
  </code></pre>
  
  <p>or there may be a single number like <code>919981424199</code>.</p>
  
  <p>I was able to do one thing. My text box is only containing a number by using this regular expression validation. In its property->Validation Expression I wrote "[0-9]+".
  This is working, but now my requirement is to send bulk SMS, and each number is separated by (,).
  I tried a lot, but I am not getting the answer. What is it?</p>