title: How to filter GridTemplateColumns of Telerik's RadGrid
body: <p>I have two <code>GridTemplateColumn</code>s in my <code>RadGrid</code>. The default filtering doesn't work for me and I want to change it.</p>
  
  <p>The GridTemplateColumns are like below:   </p>
  
  <pre><code>&lt;telerik:GridTemplateColumn FilterControlAltText="Filter Online column" HeaderText="Online"
      UniqueName="Online"&gt;
      &lt;ItemTemplate&gt;
          &lt;asp:CheckBox ID="chkOnline" runat="server" Checked='&lt;%# CheckForOnline(Eval("ID")) %&gt;'
              Enabled="False" /&gt;
      &lt;/ItemTemplate&gt;
      &lt;HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" /&gt;
      &lt;ItemStyle HorizontalAlign="Center" VerticalAlign="Middle" Width="100px" /&gt;
  &lt;/telerik:GridTemplateColumn&gt;
  </code></pre>
  
  <p>and the other one:  </p>
  
  <pre><code>&lt;telerik:GridTemplateColumn FilterControlAltText="Filter FileSize column" HeaderText="FileSize"
      UniqueName="FileSize" Visible="False"&gt;
      &lt;ItemTemplate&gt;
          &lt;asp:Label ID="lblFileSize" runat="server" Text='&lt;%# Eval("FileSize") %&gt;'&gt;&lt;/asp:Label&gt;
      &lt;/ItemTemplate&gt;
      &lt;HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" /&gt;
      &lt;ItemStyle HorizontalAlign="Center" VerticalAlign="Middle" /&gt;
  &lt;/telerik:GridTemplateColumn&gt;
  &lt;telerik:GridTemplateColumn FilterControlAltText="Filter FileSizeChange column" HeaderText="FileSize"
      UniqueName="FileSizeChange"&gt;
      &lt;ItemTemplate&gt;
          &lt;asp:Label ID="lblFileSizeChange" runat="server" Text='&lt;%# ChangeFileSize(Eval("FileSize")) %&gt;'&gt;&lt;/asp:Label&gt;
      &lt;/ItemTemplate&gt;
      &lt;HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" /&gt;
      &lt;ItemStyle HorizontalAlign="Center" VerticalAlign="Middle" /&gt;
  &lt;/telerik:GridTemplateColumn&gt;
  </code></pre>
  
  <p>As you can see, <code>FileSize</code> <code>TemplateColumn</code> is disabled and I am using <code>FileSizeChange</code> instead.</p>
  
  <p>FileSize string is like (213435) -> this number shows us bytes. FileSizeChange is like (231 MB)/</p>
  
  <p>How can I write filtering for both <code>Online</code> and <code>FileSizeChange</code> <code>GridTemplateColumn</code>s?   </p>