后台如何取到Itemtemplate里TextBox的属性，我想改变TextBox的只读属性？

GridView里放入ItemTemplate，后台如何取到Itemtemplate里TextBox的属性，我想改变TextBox的只读属性？

   <asp:UpdatePanel ID="pnlUpdate" runat="server">
            <ContentTemplate>
                <div class="FormGridClass" style="height: 355px; overflow-y: auto; margin-right: 3px;">
                    <wgv:WebGridView ID="wgvDetailOrder" DataKeyNames="seq" runat="server" Width="99%"
                        CheckBoxType="ChkNO" OnRowDataBound="wgvDetailOrder_RowDataBound" EmptyDataText="<span style='color:Red'>&nbsp;&nbsp;&nbsp;没有运单明细！</span>">
                        <Columns>
                            <asp:BoundField DataField="SEQ" HeaderText="序号" ReadOnly="true" ItemStyle-Width="30px" />
                            <asp:BoundField DataField="TASK" HeaderText="任务内容" ReadOnly="true" ItemStyle-Width="100px" />
                            <asp:TemplateField HeaderText="第一周进度" ShowHeader="true">
                                <ItemStyle CssClass="cellPadding" HorizontalAlign="Center" Width="100px" />
                                <ItemTemplate>
                                    <asp:TextBox ID="txtFPro" runat="server" Width="100px" Text='<%#Eval("FirstProcess")%>'></asp:TextBox>
                                </ItemTemplate>
                            </asp:TemplateField>
                            <asp:TemplateField HeaderText="确认人" ShowHeader="true">
                                <ItemStyle CssClass="cellPadding" HorizontalAlign="Center" Width="50px" />
                                <ItemTemplate>
                                    <asp:TextBox ID="txtFCon" runat="server" Width="50px" Text='<%#Eval("FirstConfirmer")%>'></asp:TextBox>
                                </ItemTemplate>
                            </asp:TemplateField>