Template different for an edit and an insert

[Blop]

Hello 
I've a radgridview with a datasource.

For a certain column I need to call a function which return a string, here's what I do (simplified)

<telerik:GridTemplateColumn>
                            <ItemTemplate>
                                <%# Functions.GetTheString(Eval("ID")) %>
                            </ItemTemplate>
                            <EditItemTemplate>
                                    <telerik:RadTextBox id="editString"   Text='Functions.GetTheString(Eval("ID")) ' ></telerik:RadTextBox>
                            </EditItemTemplate>
  </telerik:GridTemplateColumn>

It works fine for the edit but I m not able to do an insert anymore... Chrome console says It can't convert the dbnull into integer... How can I get an empty text box for an insert and calling my function for an edit?

Thanx in advance

[Jayesh Goyani]

Hello Blop,

<telerik:GridTemplateColumn DataField="NO" FilterControlAltText="Filter NO column"
                      HeaderText="NO" SortExpression="NO" UniqueName="NO" DataType="System.Int64">
                      <InsertItemTemplate>
                          <telerik:RadNumericTextBox runat="server" ID="txtNo">
                          </telerik:RadNumericTextBox>
                      </InsertItemTemplate>
                      <EditItemTemplate>
                          <telerik:RadComboBox ID="RadComboBox1" runat="server">
                          </telerik:RadComboBox>
                      </EditItemTemplate>
                      <ItemTemplate>
                          <%# Eval("NO") %>
                      </ItemTemplate>
                  </telerik:GridTemplateColumn>

Thanks,
Jayesh Goyani