Asp.net 输入的值不在代码中

我正在努力学习ASPX，正在做一个网站（学习目的）

我在网格视图中有一个员工列表，当单击列表中的某个名称时，我必须将该值传递给db，并在单独的页面中显示详细信息。 我是通过使用这段代码来实现的

LinkButton lnkCustomerID = sender as LinkButton;
string strCustomerID = lnkCustomerID.CommandArgument;
Response.Redirect("EmployeeDetail.aspx?Parameter=" + strCustomerID);

它工作得很好

在详细信息页面中，我在另一个网格中显示详细信息，我使用下面的代码完成了这项工作

 SqlCommand cmdCustomerDetails = new SqlCommand("GetEmployee", sqlConnect);
             cmdCustomerDetails.CommandType = CommandType.StoredProcedure;
             cmdCustomerDetails.Parameters.AddWithValue("@ID", employeeId);
             if (sqlConnect.State == ConnectionState.Closed)
                 sqlConnect.Open();
             //Create DataReader to read the record
             SqlDataReader dReader = cmdCustomerDetails.ExecuteReader();
             GridView2.DataSource = dReader;
             GridView2.DataBind();
             sqlConnect.Close();

它也起作用，但当我试图通过单击更新按钮来更新值时，它是一个项目模板，如图所示

<asp:GridView ID="GridView2" runat="server" CellPadding="4" ForeColor="#333333" GridLines="None"
        AutoGenerateColumns="False">
        <Columns>
            <asp:TemplateField HeaderText="Name">
                <ItemTemplate>
                    <asp:TextBox ID="txtName" runat="server" Text='<%# Eval("name")%>'></asp:TextBox>
                    <asp:RequiredFieldValidator ID="rqdfldName" runat="server" ErrorMessage="Name Cannot Be Empty"
                        ViewStateMode="Disabled" ControlToValidate="txtName" ValidationGroup="Update"></asp:RequiredFieldValidator>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField HeaderText="Age">
                <ItemTemplate>
                    <asp:TextBox ID="txtAge" runat="server" Text='<%# Eval("age")%>'></asp:TextBox>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField HeaderText="Address">
                <ItemTemplate>
                    <asp:TextBox TextMode="MultiLine" ID="txtAddress" runat="server" Text='<%# Eval("address")%>'></asp:TextBox>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
                <ItemTemplate>
                    <asp:Button ID="btnUpdate" runat="server" Text="Update" ValidationGroup="Update"
                        CommandArgument='<%#Eval("id") %>' OnClick="btnUpdate_Click" />
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
        <AlternatingRowStyle BackColor="White" />
        <EditRowStyle BackColor="#7C6F57" />
        <FooterStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
        <HeaderStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
        <PagerStyle BackColor="#666666" ForeColor="White" HorizontalAlign="Center" />
        <RowStyle BackColor="#E3EAEB" />
        <SelectedRowStyle BackColor="#C5BBAF" Font-Bold="True" ForeColor="#333333" />
        <SortedAscendingCellStyle BackColor="#F8FAFA" />
        <SortedAscendingHeaderStyle BackColor="#246B61" />
        <SortedDescendingCellStyle BackColor="#D4DFE1" />
        <SortedDescendingHeaderStyle BackColor="#15524A" />
    </asp:GridView>

---

当两个网格视图位于同一页面时，我可以进行更新，但当我将第二个网格移动到新页面时，更新不起作用。。请帮助我解决问题

如果没有在页面加载功能中发回，我可以通过填充数据网格来解决问题

<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.master" EnableEventValidation="false" AutoEventWireup="true" CodeFile="EmployeeDetail.aspx.cs" Inherits="EmployeeDetail" %>

int empID;
        string age, address, name;
        Button btnUpdateUser = sender as Button;
        TextBox tbName, tbAge, tbAddress;
        SqlConnection sqlConnect;
        try
        {
            tbName = (TextBox)GridView2.Rows[0].FindControl("txtName");
            tbAge = (TextBox)GridView2.Rows[0].FindControl("txtAge");
            tbAddress = (TextBox)GridView2.Rows[0].FindControl("txtAddress");
            sqlConnect = new SqlConnection("server=WINNER-PC\\SQLEXPRESS;integrated security=true;initial catalog=Test");
            if (sqlConnect.State == ConnectionState.Closed)
                sqlConnect.Open();
            empID = Convert.ToInt32(btnUpdateUser.CommandArgument);
            name = tbName.Text;
            age = tbAge.Text;
            address = tbAddress.Text;
            SqlCommand sqlCommand = new SqlCommand("UpdateEmployee", sqlConnect);
            sqlCommand.CommandType = CommandType.StoredProcedure;
            sqlCommand.Parameters.AddWithValue("@ID", empID);
            sqlCommand.Parameters.AddWithValue("@Name", name);
            sqlCommand.Parameters.AddWithValue("@Age", age);
            sqlCommand.Parameters.AddWithValue("@Address", address);
            sqlCommand.ExecuteNonQuery();
            Response.Redirect("Employees.aspx", false);
        }
        catch (Exception ex)
        {
            throw ex;
        }