title: Check multiple items in ASP.NET CheckboxList
body: <p>I try to check multiple values in ASP.NET CheckboxList but I couldn't.
  <br>
  I Wrote : </p>
  
  <pre><code>chkApplications.SelectedValue = 2;
  chkApplications.SelectedValue = 6;
  </code></pre>
  
  <p>But it just selects item with value '6'<br>
  What's wrong ?</p>