title: listbox.Items.Count is equal to zero in code
body: <p>I have two listboxes in my aspx page,which i called them ListBox1 and ListBox2. <br />
  <img src="https://i.stack.imgur.com/5KJEI.png" alt=""><br />
  I set the datasource of ListBox1 in pageload but ListBox2 is empty. </p>
  
  <pre><code>protected void btnSubmit_Click(object sender, EventArgs e)
      {
          for (int count = 0; count &lt;= Convert.ToInt32(lbright.Items.Count); count++)
          {
              string str = null;
              string[] strArr = null;
              int count2 = 0;
              str = lbright.Items[count].ToString();
              char[] splitchar = { ';' };
              strArr = str.Split(splitchar);
              for (count2 = 0; count2 &lt;= strArr.Length - 1; count++)
              {
                  Response.Write(
                      "Option" + count + ":&lt;br /&gt;" +
                      "   " + "Value" + count2 + ":" + strArr[count]
                      );
              }
          }
      }
  </code></pre>
  
  <p>The user can double click on items in ListBox1 to add them to ListBox2.I have wrote this code in JQuery.Everything works fine in this part.<br /></p>
  
  <pre><code>&lt;script type="text/javascript"&gt;
  $(document).ready(function () {
      $('#lbleft').on('dblclick', 'option', function () {
          var element = $("#lbleft option:selected");
          var value = element.val();
          var text = element.text();
          element.remove();
  
          $("#lbright").append('&lt;option value="' + value + '"&gt;' + text + '&lt;/option&gt;');
      });
      $('#lbright').on('dblclick', 'option', function () {
          var element = $("#lbright option:selected");
          var value = element.val();
          var text = element.text();
          element.remove();
  
          $("#lbleft").append('&lt;option value="' + value + '"&gt;' + text + '&lt;/option&gt;');
      });
  });
  </code></pre>
  
  <p></p>
  
  <p>The problem is when i want to read items from ListBox2.<br />
  I have a button in my page which user can save items of ListBox2 by clicking on this button.but the count of items of ListBox2 is zero in codebehind.</p>