Use of Hiddenfield in a GridTemplateColumn

[Adigard]

Greetings,

I have a problem in the following code:

<telerik:GridTemplateColumn>
    <ItemTemplate>
        <asp:HiddenField ID="HiddenFieldIdParticipant" runat="server" Value='<%#Eval("idUtilisateur")%>' />
    </ItemTemplate>
</telerik:GridTemplateColumn>

code behind:

HiddenField HiddenFieldIdParticipant = GridDisplayOldRDV.FindControl("HiddenFieldIdParticipant") as HiddenField;

This is not working i don't get anything in my hiddenfield
Does anyone know why ?
Thx in advance!

[Adigard]

HiddenField HiddenFieldIdParticipant = e.Item.FindControl("HiddenFieldIdParticipant") as HiddenField;

[ali haririan]

thank you its currect

asp.net >>> in your radgrid

                               <telerik:GridTemplateColumn>
                                    <ItemTemplate>
                                        <asp:HiddenField ID="HiddenFieldIdParticipant" runat="server" Value='<%#Eval("id")%>' />
                                    </ItemTemplate>
                                </telerik:GridTemplateColumn>
C#
protected void RadGrid1_ItemCommand(object sender, Telerik.Web.UI.GridCommandEventArgs e)
        {
            if (e.CommandName == "delete")
            {
                HiddenField HiddenFieldIdParticipant = e.Item.FindControl("HiddenFieldIdParticipant") as HiddenField;
                int id = Convert.ToInt32(HiddenFieldIdParticipant.Value);
............................
            }
        }