Why is localization not working for gridvew?

Why is my localization not working with gridview ?

I have made resx files:

BoundFieldLCode.HeaderText      کد زبان 
BoundFieldText.HeaderText           متن 

and bound fields:

 <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" DataKeyNames="ID">
        <Columns>
            <asp:BoundField DataField="Text" HeaderText="Text" meta:resourceKey="BoundFieldText" />
            <asp:BoundField DataField="Language" HeaderText="Language Code" meta:resourceKey="BoundFieldLCode" />
        </Columns>
    </asp:GridView>

and put this in header of page directive

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Report.aspx.cs" Inherits="_Default"  Culture="auto:en-US" UICulture="auto" %>

via Chebli Mohamed