radio buttons selected values is not working - asp.net

Question

I have tried to select radio button from selected value of a drop down like this
Dim ddlupd As DropDownList = CType(grid.HeaderRow.FindControl("dropdown"), DropDownList)
For Each gv As GridViewRow In grid.Rows
Dim rdo As RadioButtonList = CType(grid.Rows(gv.RowIndex).FindControl("list"), RadioButtonList)
Dim cat As Label = CType(grid.Rows(gv.RowIndex).FindControl("lblcat"), Label)
If cat.Text = ddlupd.SelectedItem.Text Then
rdo.SelectedValue = selflg.ToString()
ElseIf ddlupd.SelectedItem.Text = "Clear Selection" Then
rdo.ClearSelection()
ElseIf ddlupd.SelectedItem.Text = "Select All" Then
rdo.SelectedValue = selflg.ToString()
End If
Next
and there is template field in gridview like this
<asp:TemplateField HeaderText="Status">
<HeaderTemplate>
<asp:DropDownList ID="dropdown" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddlupdGM1" BackColor="#3399FF" ForeColor="White">
<asp:ListItem>Select Category</asp:ListItem>
<asp:ListItem>Clear Selection</asp:ListItem>
<asp:ListItem Value="1">Cane Payment</asp:ListItem>
<asp:ListItem Value="2">Income Tax</asp:ListItem>
<asp:ListItem Value="3">Fund Transfer</asp:ListItem>
<asp:ListItem Value="4">Others</asp:ListItem>
</asp:DropDownList>
</HeaderTemplate>
<ItemTemplate>
<asp:RadioButtonList ID="chkStatusGM" runat="server" AutoPostBack="false" RepeatDirection="Horizontal" OnSelectedIndexChanged="chkStatus_OnCheckedChangedGM">
<asp:ListItem Value="5">Approve</asp:ListItem>
<asp:ListItem Value="0">Not Approved</asp:ListItem>
</asp:RadioButtonList>
</ItemTemplate>
</asp:TemplateField>
Also I Am running a update command to database with selected values of radio button.Problem is that when select the radio button from drop down value of header template then no update runs due to null selection of radiobutton and when i manually select the radio button the update works fine.
Update
**
Protected Sub chkStatus_OnCheckedChangedGM(ByVal sender As Object, ByVal e As System.EventArgs)
Dim cmd As OleDbCommand = New OleDbCommand()
Dim chkStatusGM As RadioButtonList = CType(sender, RadioButtonList)
Dim row As GridViewRow = CType(chkStatusGM.NamingContainer, GridViewRow)
Dim bpvnum As String = row.Cells(4).Text
cmd.CommandText = "update sml.FND_01_11#wbg set sta_flg=:sta_flg where bpv_num=:bpv_num and bpv_dte=:bpv_dte"
cmd.CommandType = CommandType.Text
cmd.Connection = con
cmd.Parameters.Add(":sta_flg", OleDbType.BigInt).Value = chkStatusGM.SelectedValue
cmd.Parameters.Add(":bpv_num", OleDbType.BigInt).Value = bpvnum
cmd.Parameters.Add(":bpv_dte", OleDbType.Date).Value = TreeView2.SelectedValue
Try
con.Open()
cmd.ExecuteNonQuery()
con.Close()
Catch ex As Exception
Response.Write(ex.ToString())
End Try
End Sub
**

Answer 1

Call the SelectedIndexChanged event of the radio button list (or whatever event handler you are using):
Dim ddlupd As DropDownList = CType(grid.HeaderRow.FindControl("dropdown"), DropDownList)
For Each gv As GridViewRow In grid.Rows
Dim rdo As RadioButtonList = CType(grid.Rows(gv.RowIndex).FindControl("list"), RadioButtonList)
Dim cat As Label = CType(grid.Rows(gv.RowIndex).FindControl("lblcat"), Label)
If cat.Text = ddlupd.SelectedItem.Text Then
rdo.SelectedValue = selflg.ToString()
ElseIf ddlupd.SelectedItem.Text = "Clear Selection" Then
rdo.ClearSelection()
ElseIf ddlupd.SelectedItem.Text = "Select All" Then
rdo.SelectedValue = selflg.ToString()
End If
' call the event handler similar to manually clicking an option
chkStatus_OnCheckedChangedGM(rdo, new System.EventArgs())
Next