DropDownList - OnTextChanged

Dear all,
How come this OnTextChanged doesn't call the sub behind? How to make the OnTextChanged works properly? All I want is when I change the selection, it will call the sub behind.

Checkout.aspx

<asp:FormView ID="frmCheckOut" runat="server" DataSourceID="dtsOrder">
   
  <InsertItemTemplate>   
    <asp:DropDownList ID="lstPaymentModeCode" runat="server" DataSourceID="dtsPaymentMode" DataTextField="Description" DataValueField="Code" OnTextChanged="lstPaymentModeCode_click"/>
  </InsertItemTemplate>
 
</asp:FormView>


Checkout.aspx.vb

Protected Sub lstPaymentModeCode_click()
  MsgBox("It does not call this sub")
End Sub
Thanks in advance
Keiko   ...