not able to get the dropdown values

<asp:TemplateField HeaderText="From Period" HeaderStyle-HorizontalAlign="Left">
                                  <edititemtemplate>
                                      <asp:DropDownList ID="cmbFrm" runat="server" Style="width: 150px;"
                                          DataSourceID="dsOtherDept1" DataTextField="FromPeriod" DataValueField="FromPeriod"
                                          AppendDataBoundItems="true">
                                          <asp:ListItem Text="Please Select" Value="">

                                  </edititemtemplate>
                                  <itemtemplate>
                                      <asp:Label ID="lblFrm" runat="server" Text='<%# Eval("FromPeriod") %>'>
                                  </itemtemplate>
                                   <HeaderStyle HorizontalAlign="Left" />

                               <asp:TemplateField HeaderText="To Period" HeaderStyle-HorizontalAlign="Left">
                                  <edititemtemplate>
                                      <asp:DropDownList ID="cmbTo" runat="server" Style="width: 150px;"
                                          DataSourceID="dsOtherDept1" DataTextField="ToPeriod" DataValueField="ToPeriod"
                                          AppendDataBoundItems="true">
                                          <asp:ListItem Text="Please Select" Value="">

                                  </edititemtemplate>
                                  <itemtemplate>
                                      <asp:Label ID="lblTo" runat="server" Text='<%# Eval("ToPeriod") %>'>
                                  </itemtemplate>
                                   <HeaderStyle HorizontalAlign="Left" />

                              <asp:TemplateField HeaderText="Edit" ShowHeader="False" HeaderStyle-HorizontalAlign="Left">
                                  <edititemtemplate>
                                      <asp:LinkButton ID="lbkUpdate" runat="server" CausesValidation="True" CommandName="Update"  CommandArgument='<%#Eval("emp_number") %>' Text="Update">
                                      <asp:LinkButton ID="lnkCancel" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel">
                                  </edititemtemplate>
                                  <itemtemplate>
                                      <asp:LinkButton ID="lnkEdit" runat="server" CausesValidation="False" CommandName="Edit"  CommandArgument='<%#Eval("emp_number") %>' Text="Edit">
                                  </itemtemplate>
                                  <HeaderStyle HorizontalAlign="Left" />

                              <asp:CommandField HeaderText="Delete" ShowDeleteButton="True" ShowHeader="True" />


                  <asp:SqlDataSource ID="dsOtherDept1" runat="server"
                          ConnectionString="<%$ConnectionStrings:MPP%>"
                          SelectCommand="Select distinct V.emp_number as emp_number,emp_name+' '+emp_initial as name,emp_designation,Manpower_Division_ID,FromPeriod, ToPeriod from idpeapp.dbo.view_employee V inner join OtherDeptEmp O on V.emp_number = O.emp_number order by name">

Protected Sub grdDeptEmp_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles grdDeptEmp.RowCommand
       'Dim list As DropDownList = TryCast(e.Row.FindControl("cmbFrm"), DropDownList)
       'cmbFrm.SelectedIndex = cmbFrm.Items.IndexOf(cmbFrm.Items.FindByValue(DataBinder.Eval(e.Row.DataItem, "FromPeriod")))
       Dim emp_number As Integer = Convert.ToInt32(e.CommandArgument)
       Dim cmbFrm As DropDownList = DirectCast(grdDeptEmp.FindControl("cmbFrm"), DropDownList)
       If e.CommandName = "update" Then
           'Dim list As DropDownList = TryCast(e.Row.FindControl("cmbFrm"), DropDownList)
           'get the EmpNo of the clicked row
           'dsOtherDept1.UpdateCommand  = "update OtherDeptEmp set FromPeriod='" &  & "',ToPeriod='" & & "' where emp_number= '" & EmpNo & "'"
           'dsOtherDept1.DataBind()
       End If
   End Sub