title: GridViewDataComboBoxColumn in ASPxGridView does not bind to EntityDataSource
body: <p>I have an <code>ASPxGridView</code> bound to an <code>EntityDataSource</code>. One of my columns needs to reference a column from another entity, so I decided to make it a <code>GridViewDataComboBoxColumn</code>. My .aspx code is the following:</p>
  
  <pre><code>&lt;dx:ASPxGridView ID="gridDocumente" runat="server" DataSourceID="EDS" KeyFieldName="IDDocument" OnDataBinding="gridDocumente_DataBinding" AutoGenerateColumns="False" Theme="Moderno"&gt;
      &lt;Settings ShowFilterRow="True" /&gt;
      &lt;SettingsSearchPanel Visible="True" /&gt;
      &lt;Columns&gt;
          &lt;dx:GridViewCommandColumn ShowDeleteButton="true" ShowUpdateButton="true" VisibleIndex="0" ShowClearFilterButton="True" ShowEditButton="True" ShowNewButtonInHeader="True"&gt;&lt;/dx:GridViewCommandColumn&gt;
          &lt;dx:GridViewDataColumn FieldName="IDDocument" VisibleIndex="1" Visible="false"&gt;&lt;EditFormSettings Visible="False" /&gt;&lt;/dx:GridViewDataColumn&gt;
          &lt;dx:GridViewDataColumn FieldName="NrInregistrare" VisibleIndex="2"&gt;&lt;/dx:GridViewDataColumn&gt;
          &lt;dx:GridViewDataColumn FieldName="DataInregistrare" VisibleIndex="3"&gt;&lt;/dx:GridViewDataColumn&gt;
          &lt;dx:GridViewDataColumn FieldName="TipD" VisibleIndex="4"&gt;&lt;/dx:GridViewDataColumn&gt;
          &lt;dx:GridViewDataColumn FieldName="NumeDocument" VisibleIndex="5"&gt;&lt;/dx:GridViewDataColumn&gt;
          &lt;dx:GridViewDataColumn FieldName="Descriere" VisibleIndex="6"&gt;&lt;/dx:GridViewDataColumn&gt;
          &lt;dx:GridViewDataComboBoxColumn FieldName="TipDocument" VisibleIndex="7"&gt;
              &lt;PropertiesComboBox DataSourceID="EDSTipDocument" ValueField="IDTipDocument"  TextField="NumeTipDocument" ValueType="System.Int32"&gt;&lt;/PropertiesComboBox&gt;
          &lt;/dx:GridViewDataComboBoxColumn&gt;
      &lt;/Columns&gt;
  &lt;/dx:ASPxGridView&gt;
  &lt;ef:EntityDataSource ID="EDSTipDocument" runat="server" ContextTypeName="Users.Models.DocumentContext" EntitySetName="TipuriDocumente" OnContextCreating="EDS_ContextCreating"&gt;&lt;/ef:EntityDataSource&gt;
  &lt;ef:EntityDataSource ID="EDS" runat="server" ContextTypeName="Users.Models.DocumentContext" EntitySetName="Documente" EnableDelete="true" EnableUpdate="true" OnContextCreating="EDS_ContextCreating"&gt;&lt;/ef:EntityDataSource&gt;
  </code></pre>
  
  <p>Although I have tried to follow the examples found on the Internet, the <code>GridViewDataComboBoxColumn</code> will not bind to <code>EDSTipDocument</code> datasource, it shows nothing in the grid.</p>
  
  <p>Could you please help me?</p>
  
  <p>Thank you very much!</p>