title: Setting DataSource to DataGridViewComboBoxColumn
body: <p>I'm trying to set DataSource to DataGridViewComboBoxColumn of my DataGridView. First I'm trying to bind a data source to my DataGridView, where bindingList is a List of my custom class Plugin with properties Name (string), Id (string) and Dependencies (List):</p>
  
  <pre><code>var bindingList = PluginsHandler.GetPlugins();
  var source = new BindingSource(bindingList, null);
  
  
  pluginsDataGridView.AutoGenerateColumns = false;
  pluginsDataGridView.DataSource = source;
  
  pluginsDataGridView.Columns["pluginName"].DataPropertyName = "Name";
  pluginsDataGridView.Columns["pluginID"].DataPropertyName = "Id";
  </code></pre>
  
  <p>So I can set my first two columns, but now I want to bind data to a third column of type DataGridViewComboBoxColumn. I try to do it on DataBindingComplete event:</p>
  
  <pre><code>private void pluginsDataGridView_DataBindingComplete(object sender, DataGridViewBindingCompleteEventArgs e)
  {
      for (int i = 0; i &lt; pluginsDataGridView.Rows.Count; i++)
      {
          var comboCell = (DataGridViewComboBoxCell) pluginsDataGridView.Rows[i].Cells["pluginDependencies"];
          var entry = pluginsDataGridView.Rows[i].DataBoundItem as IPlugin;
          comboCell.DataSource = entry.Dependencies;    
      }
  
  }
  </code></pre>
  
  <p>Sadly comboBox is empty. Funny thing happens when I incorrectly put these lines after the first block of code I posted:</p>
  
  <pre><code>  var dependenciesColumn = (DataGridViewComboBoxColumn) pluginsDataGridView.Columns["pluginDependencies"];
    dependenciesColumn.DataPropertyName = "Dependencies";
  </code></pre>
  
  <p>Then binding seem to start to work, as I can see that there are some entries in comboboxes, but when I try to hover mouse on combobox, I am getting an error that says DataGridViewComboBoxCell value is not valid).</p>
  
  <p>How can I make it work?</p>