how to reach grid columns after setting datasource

[Nazim]

I am getting follwing error when I try to get grid columns after setting data soure a table which AutoGenerateColumns property is true.  The bold line throws an exception whit message "Cannot find column bound to field 'date" even  the datatable has that column. I thought that may be a problem with rendering such it is not populated yet. Then I put that code in the columns created event and also pre render event. Result has not changed yet. Is there anyone faced tihs problem before?
Thnaks,


telerik:RadGrid ID="rgridDeliveryDate" skin="Mar"
              Width="100%" AutoGenerateColumns="true" AllowMultiRowSelection="True"           
              runat="server" Gridlines="None" EnableEmbeddedSkins="false">                
              <ClientSettings EnableRowHoverStyle="true">                  
                <Selecting AllowRowSelect="True"></Selecting>
                <Resizing AllowRowResize="True" EnableRealTimeResize="True" ResizeGridOnColumnResize="True"
                    AllowColumnResize="True"></Resizing>
              </ClientSettings>
           <MasterTableView Width="100%" Summary="" NoMasterRecordsText="Servis saatleri set edilmemis" >    
             
           </MasterTableView>           
        </telerik:RadGrid>

code behind
DataTable dt = mh.GetServicePeriods();
rgridDeliveryDate.PreRender += new EventHandler(rgridDeliveryDate_PreRender);
rgridDeliveryDate.DataSource = dt;
rgridDeliveryDate.DataBind();

GridBoundColumn grdCol = rgridDeliveryDate.Columns.FindByDataField("date") as GridBoundColumn;
grdCol.DataFormatString = "dd/MM/yyyy";
grdCol.HeaderText = "";

[Pavlina]

Hi Nazim,

You can customize the properties of auto-generated columns at runtime by providing a handler for the grid's ColumnCreated event. In the event handler, cast the column to the appropriate type and set its attributes. You can review the following help article for more information:
http://www.telerik.com/help/aspnet-ajax/grdusingcolumns.html

Greetings,
Pavlina
the Telerik team