Gridview -TemplateField -HiddenField How to set data from code?

Hi,


I have a gridview which has hidden fields inside.
<asp:GridView ID="GridView" runat="server" AutoGenerateColumns="False" CssClass="gridview"> <Columns> <asp:BoundField DataField="mtipitext" HeaderText="<%$ Resources:Masraf, mtipi %>" HtmlEncode="False" /> <asp:BoundField DataField="mtipi" HeaderText="<%$ Resources:Masraf, mtipi %>" HtmlEncode="False" /> <asp:TemplateField> <ItemTemplate> <asp:HiddenField runat="server" ID="HiddenField_PBirim" /> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText=&q ...