RadComboBox in GridTemplateColumn with EntityDataSource

[Nor]

Hi.

I have a RadComboBox in a GridTemplateColumn's EditTemplate like this:

....
<telerik:GridTemplateColumn UniqueName="Unit.Name" HeaderText="Unit" DataField="Unit.Id"

    SortExpression="Unit.Id" ItemStyle-Width="250px">

    <ItemTemplate>

        <%# DataBinder.Eval(Container.DataItem, "Unit.Name")%>

    </ItemTemplate>

    <EditItemTemplate>

        <telerik:RadComboBox runat="server" ID="UnitComboBox" EnableLoadOnDemand="True" SelectedValue='<%#Bind("Unit.Id")%>'

            DataTextField="Name" DataSourceID="UnitEntityDataSource"

            DataValueField="Id" AutoPostBack="true" HighlightTemplatedItems="true" Height="250px" Width="250px" DropDownWidth="600px">
....

The Grid uses one EntityDataSource and the combobox another.

This works perfectly when updating existing rows, but when I insert a new row it crashes with:

DataBinding: 'Telerik.Web.UI.GridInsertionObject' does not contain a property with the name 'Unit'.

I guess this is because Unit is null when I insert a new object and therefore cant resolve Unit.Id. 

All the existing solutions recommend that you cancel the insert command and insert a dummy row, this would work if it was a ordinary column, but since its an entity I have to specify the relation, hence Unit.Id and not UnitId (which is the columnname in the grids entitydatasource)

I suspect this is the same problem that FreshOne reported here: Forum link

Ive also tried to behind selectedvalue code behind (trying to distinguish between update and insert) but then no values get updated instead.

Can I clarify my problem further?
Best Regards 
N.

[Mira]

Hello Nor,

When you use Load On Demand or Automatic Load On Demand of the RadComboBox,  you should add the previously selected item on ItemDataBound of the grid only when in 'Edit' Mode.
You can see how it is done in the Combo in Grid demo.

I hope this helps.

Greetings,
Mira
the Telerik team

[Nor]

Ok, I understand, but it doesn't fix my problem. 
Edit works well, its insert that doesn't work. Mainly because I cant do a 

'<%#Bind("Unit.Id")%>'

(I'm guessing here)
Since Unit is Null (remember i'm using EF datasource).

Can I somehow only set selectedvalue on a update?

[Nor]

Ok, I fixed it. I link Mira posted sent me in the right direction.
Anyway, the solution went from simple to quite complicated.

I had to save the selected value in the Session, like the link suggested, however is this really a good idea? What should I have done if I had multiple rows to edit at the same time?

Anyway, I still feel like there should be an easier solution.

Thanks.

[Mira]

Hello Nor,

If you do not want to store the value of the selected item in session, you can set only the SelectedText property of the RadComboBox.
Another option is to use the GridDropDownColumn which as of version 2010.Q2 of Telerik RadControls supports automatic load-on-demand for the RadComboBox editor.
Please examine the Customize/configure GridDropDownColumn help topic for additional information.

I hope this helps.

Kind regards,
Mira
the Telerik team