title: Add custom properties to ASP.net checkboxlist
body: <p>Checkbox list items have default "Text", "Value", "Enabled" and "Selected" properties.</p>
  
  <p>I need to add an "ImageUrl" property to each item in my list.
  I use this code:</p>
  
  <pre><code>foreach (Zone zn in ZonesList)
  {
      ListItem item = new ListItem(zn.Name, zn.Id.ToString());
      item.Attributes.Add("ImageUrl", zn.Image );
      item.Selected = false;
  
      visitPlaceList.Items.Add(item);
  }
  
  visitPlaceList.DataBind();
  </code></pre>
  
  <p>but it still doesn't show any properties other than the defaults.</p>
  
  <p>How can this be achieved?</p>