有码求解，更新问题

Question

想要实现的功能，在编辑行的时候自动把当前的用户名写入数据库
目前我用response显示((TextBox)(GridView1.Rows[e.RowIndex].Cells[4].Controls[0])).Text，正确显示当前用户名，
但是并没有写入到数据库
html：
<%@ Page Language="C#" MasterPageFile="~/User2/MasterPage.master" AutoEventWireup="true" CodeFile="CaseLV.aspx.cs" Inherits="User2_CaseLV" Title="Untitled Page" %><asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
    <p>
        <asp:Button ID="Button3" runat="server" Text="未处理" />
        <asp:Button ID="Button4" runat="server" Text="已处理" 
            PostBackUrl="~/User2/CASELV2.aspx" />
    </p>
<p>
        <asp:TextBox ID="TextBox1" runat="server" Width="78px"></asp:TextBox>
        <asp:Button ID="Button1" runat="server" Text="日期" onclick="Button1_Click" />
        <asp:Button ID="Button2" runat="server" Text="确定" />
    </p>
<p>
        <asp:Calendar ID="Calendar1" runat="server" BackColor="#FFFFCC" 
            BorderColor="#FFCC66" BorderWidth="1px" DayNameFormat="Shortest" 
            Font-Names="Verdana" Font-Size="8pt" ForeColor="#663399" Height="87px" 
            onselectionchanged="Calendar1_SelectionChanged" ShowGridLines="True" 
            Visible="False" Width="57px">
            <SelectedDayStyle BackColor="#CCCCFF" Font-Bold="True" />
            <SelectorStyle BackColor="#FFCC66" />
            <TodayDayStyle BackColor="#FFCC66" ForeColor="White" />
            <OtherMonthDayStyle ForeColor="#CC9966" />
            <NextPrevStyle Font-Size="9pt" ForeColor="#FFFFCC" />
            <DayHeaderStyle BackColor="#FFCC66" Font-Bold="True" Height="1px" />
            <TitleStyle BackColor="#990000" Font-Bold="True" Font-Size="9pt" 
                ForeColor="#FFFFCC" />
        </asp:Calendar>
    </p>
<p>
        <asp:GridView ID="GridView1" runat="server" AllowPaging="True" 
            AllowSorting="True" AutoGenerateColumns="False" CellPadding="4" 
            DataSourceID="SqlDataSource1" ForeColor="#333333" GridLines="None" 
            DataKeyNames="id" onrowupdating="GridView1_RowUpdating" >
            <RowStyle BackColor="#EFF3FB" />
            <Columns>
                <asp:CommandField ShowEditButton="True" EditText="选择" UpdateText="确定" />
                <asp:BoundField DataField="id" HeaderText="id" SortExpression="id" 
                    InsertVisible="False" ReadOnly="True" Visible="False">
                </asp:BoundField>
                <asp:BoundField DataField="caseid" HeaderText="caseid" 
                    SortExpression="caseid" >
                <ItemStyle Width="300px" />
                </asp:BoundField>
                <asp:BoundField DataField="aggent" HeaderText="aggent" 
                    SortExpression="aggent" Visible="False" />
                <asp:BoundField DataField="folt2" HeaderText="folt2" 
                    SortExpression="folt2" Visible="False" />
                <asp:BoundField DataField="folt" HeaderText="folt" 
                    SortExpression="folt" />
                <asp:BoundField DataField="casetime" HeaderText="升级时间" 
                    SortExpression="casetime" />
            </Columns>
            <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
            <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
            <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
            <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
            <EditRowStyle BackColor="#2461BF" />
            <AlternatingRowStyle BackColor="White" />
        </asp:GridView>
    </p>
<p>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
            ConnectionString="<%$ ConnectionStrings:MuserConnectionString2 %>" 
            DeleteCommand="DELETE FROM [caselv] WHERE [id] = @id" 
            InsertCommand="INSERT INTO [caselv] ([caseid], [aggent], [folt2], [folt], [casetime]) VALUES (@caseid, @aggent, @folt2, @folt, @casetime)" 
            SelectCommand="SELECT [id], [caseid], [aggent], [folt2], [folt], [casetime] FROM [caselv] WHERE (([casetime] &gt; @casetime) AND ([folt2] = @folt2))" 
            UpdateCommand="UPDATE [caselv] SET [caseid] = @caseid, [aggent] = getdate(), [folt2] = '已处理', [folt] = @folt, [casetime] = @casetime WHERE [id] = @id">
            <SelectParameters>
                <asp:ControlParameter ControlID="TextBox1" Name="casetime" PropertyName="Text" 
                    Type="DateTime" />
                <asp:Parameter DefaultValue="未处理" Name="folt2" Type="String" />
            </SelectParameters>
            <DeleteParameters>
                <asp:Parameter Name="id" Type="Int32" />
            </DeleteParameters>
            <UpdateParameters>
                <asp:Parameter Name="caseid" Type="String" />
                <asp:Parameter Name="aggent" Type="DateTime" />
                <asp:Parameter Name="folt2" Type="String" />
                <asp:Parameter Name="folt" Type="String"/>
                <asp:Parameter Name="casetime" Type="DateTime" />
                <asp:Parameter Name="id" Type="Int32" />
            </UpdateParameters>
            <InsertParameters>
                <asp:Parameter Name="caseid" Type="String" />
                <asp:Parameter Name="aggent" Type="DateTime" />
                <asp:Parameter Name="folt2" Type="String" />
                <asp:Parameter Name="folt" Type="String" />
                <asp:Parameter Name="casetime" Type="DateTime" />
            </InsertParameters>
        </asp:SqlDataSource>
        <br />
    </p>
    <p>
        &nbsp;</p>
    <p>
        &nbsp;</p>
    <p>
        &nbsp;</p>
    <p>
        &nbsp;</p>
    <p>
        &nbsp;</p>
    <p>
        &nbsp;</p>
    <p>
        &nbsp;</p>
    <p>
        &nbsp;</p>
    <p>
    </p>
    <p>
    </p>
</asp:Content>代码
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;public partial class User2_CaseLV : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string userna = (string)Session["UserName"];
        Response.Write(userna);
    }
    protected void Calendar1_SelectionChanged(object sender, EventArgs e)
    {
        int Ya = Calendar1.SelectedDate.Year;
        int Ma = Calendar1.SelectedDate.Month;
        int Da = Calendar1.SelectedDate.Day;
        TextBox1.Text = (Ya + "/" + Ma + "/" + Da).ToString();
        Calendar1.Visible = false;
         }
    protected void Button1_Click(object sender, EventArgs e)
    {
        Calendar1.Visible = true;
    }
    protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        ((TextBox)(GridView1.Rows[e.RowIndex].Cells[4].Controls[0])).Text = (string)Session["UserName"];
    }
}