Handle Multiple Click of Radio Button inside GridView

<gridview>

<Columns>

<asp:TemplateField HeaderText="Select">

<ItemTemplate>

<asp:RadioButton ID="Rdbttn_Package" runat="server" AutoPostBack="true" Text='<%# DataBinder.Eval(Container,"DataItem.RP_SHORT_DESC") %>'

ToolTip='<%# DataBinder.Eval(Container,"DataItem.RP_AMOUNT") %>' OnCheckedChanged="Rdbttn_Package_CheckedChanged" />

</ItemTemplate>

<HeaderStyle HorizontalAlign="Right" />

</asp:TemplateField>

</Columns>

<GridView>

Dim rb As New RadioButton

Dim rbNewSelect As New RadioButton

Dim strOldSelect As String

strOldSelect = ""

Lbl_Error.Text = String.Empty

rbNewSelect = CType(sender, RadioButton)

For Each gvRow As GridViewRow In gv_RenewalSchemePackage.Rows

rb = CType(gvRow.FindControl("Rdbttn_Package"), RadioButton)

If (rb.Checked = True And rb.UniqueID <> rbNewSelect.UniqueID) Then

strOldSelect = rb.UniqueID

End If

rb.Checked = False

Next

rb.Dispose()

rbNewSelect.Checked = True

''Additional Code paste here