edit mode GridViewComboboxColumn don't work

[Jupa]

HI, I´m trying this but it's don't work

my combobox don't change to edit mode, but only the comboboxes, the textbox are editables

I try put itemsources in codebehind and nothing

<telerik:RadGridView Height="77" HorizontalAlignment="Left" Margin="36,33,0,0" Name="GrdSupExplotada"
                                       VerticalAlignment="Top" Width="356" ShowGroupPanel="False"
                                       AutoGenerateColumns="False" ShowInsertRow="True" IsFilteringAllowed="False"

                                       AddingNewDataItem="GrdSupExplotada_AddingNewDataItem" RowEditEnded="GrdSupExplotada_RowEditEnded">

                      <telerik:RadGridView.Columns>
                          <telerik:GridViewComboBoxColumn x:Name="cmbActividad" DisplayMemberPath="Nombre"
                                                          IsReadOnly="False"
                                                          IsComboBoxEditable="True"
                             UniqueName ="Nombresss"
                             SelectedValueMemberPath="IdParametro"
                              Header="Actividad" DataMemberBinding="{Binding IdTipoCategoria}">
                             <!--
                              ItemsSource="{Binding Path=Parametro, Source={StaticResource ddsActividad }}"
                              <telerik:GridViewColumn.CellTemplate>
                               <DataTemplate>
                                  <TextBlock Text="{Binding Categorie.Nome}"></TextBlock>
                              </DataTemplate>
                              </telerik:GridViewColumn.CellTemplate>-->
                              </telerik:GridViewComboBoxColumn>

                          <telerik:GridViewDataColumn Header="Superficie(ha)" DataMemberBinding="{Binding Superficie}" />
                          <telerik:GridViewDataColumn Header="Observación" DataMemberBinding="{Binding Observaciones}" />
                      </telerik:RadGridView.Columns>
                  </telerik:RadGridView>

y mi code behind

GrdSupExplotada.ItemsSource = aa;
((GridViewComboBoxColumn)this.GrdSupExplotada.Columns["Nombresss"]).ItemsSource = convert.dictGruposParametros["52"];

 my itemsSources have data.

I hope Yours could help me

the problem is the DataMemberBinding but, I don't understand why both are int32 an both are keys

[Jupa]

ja ja ja keys are no editables. I put a metadata and it work

[MahMah]

Hello Dear Jupa,

I should make a key column in a RadGridView editable too, but I can't.

What do you mean by saing " I put a metadata "

Please express more what should I do ?

Thank you a lot.

[Jupa]

In the web project, in file metadata.cs add metadata

[Editable(true, AllowInitialValue = true)]
public int IdTipoCategoria { get; set; }

to atribute, in my case IdTipoCategoria

[MahMah]

Thank you very much.