title: Adding , removing items to and from a ListBox after binding
body: <p>In following button event I'm adding items to a list from another list. </p>
  
  <pre><code>    private void btnAdd_Click(object sender, EventArgs e)
      {
          if (lstPermissions.SelectedItem != null)
          if (!lstGivenPermissions.Items.Contains(lstPermissions.SelectedItem))
          {
              lstGivenPermissions.Items.Add(lstPermissions.SelectedItem);
          }
      }
  </code></pre>
  
  <p>When the Items were hard coded in <code>lstPermissions</code> and <code>lstGivenPermissions</code>'s <code>datasource</code> is not set , it was fine. But After binding data to <code>lstGivenPermissions</code>, when I try to execute this method I'm getting this exception.</p>
  
  <p><strong><em>Items collection cannot be modified when the DataSource property is set.</em></strong></p>
  
  <p>I'm using this property to bind data to the <code>lstGivenPermissions</code></p>
  
  <pre><code>    public List&lt;string&gt;  GivenPermission
      {
          get { return lstGivenPermissions.Items.Cast&lt;string&gt;().ToList(); }
          set { lstGivenPermissions.DataSource = value; }
      }
  </code></pre>
  
  <p>I can understand that the databinding has caused this exception. But my requirement is that I want to load all permissions to <code>lstPermissions</code> and selected user's permissions to <code>lstGivenPermission</code> from the database. Then I should be able to add and remove items to and from <code>lstGivenPermissions</code>. Could you let me know how to do this?</p>