Check only one radio button which is in gridview item template

Question

Hi,

I am using below code to check only one radio button which is in gridview item template. But it allow multiple selection as CheckBoxes.

My code:

<columns>
<asp:TemplateField HeaderText="Select">
                                <ItemTemplate >
                                    <asp:RadioButton ID="rd1" GroupName="rdBox"  runat="server"  />
                                </ItemTemplate>
                               </asp:TemplateField>
</columns>

Please help me.

Thanks !

Pankaj Singh