即使我重新生成了designer.cs文件，TextBox也没有出现在代码隐藏中

我的项目有一个小问题。我在.aspx文件中添加了一些文本框，但是我不能在.aspx.designer.cs中看到它们，因此我不能在aspx.cs中使用它们。

.aspx文件:

Register.aspx:

<%@ Page Title="Register" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="True"
    CodeBehind="Register.aspx.cs" Inherits="LearnEF.Account.Register" %>
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content>

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <asp:CreateUserWizard ID="RegisterUser" runat="server" EnableViewState="false" OnCreatedUser="RegisterUser_CreatedUser">
<%--        <LayoutTemplate>
            <asp:PlaceHolder ID="wizardStepPlaceholder" runat="server"></asp:PlaceHolder>
            <asp:PlaceHolder ID="navigationPlaceholder" runat="server"></asp:PlaceHolder>
        </LayoutTemplate>--%>
        <WizardSteps>
            <asp:CreateUserWizardStep ID="RegisterUserWizardStep" runat="server">
                <ContentTemplate>
                    <h2>
                        Create a New Account
                    </h2>
                    <p>
                        Use the form below to create a new account.
                    </p>
                    <p>
                        Passwords are required to be a minimum of <%= Membership.MinRequiredPasswordLength %> characters in length.
                    </p>
                    <span class="failureNotification">
                        <asp:Literal ID="ErrorMessage" runat="server"></asp:Literal>
                    </span>
                    <asp:ValidationSummary ID="RegisterUserValidationSummary" runat="server" CssClass="failureNotification" 
                         ValidationGroup="RegisterUserValidationGroup"/>
                    <div class="accountInfo">
                        <fieldset class="register">
                            <legend>Account Information</legend>
                            <p>
                                <asp:Label ID="UserNameLabel" runat="server" AssociatedControlID="UserName">User Name:</asp:Label>
                                <asp:TextBox ID="UserName" runat="server" CssClass="textEntry" OnTextChanged="UserName_TextChanged"></asp:TextBox>
                                <asp:RequiredFieldValidator ID="UserNameRequired" runat="server" ControlToValidate="UserName" 
                                     CssClass="failureNotification" ErrorMessage="User Name is required." ToolTip="User Name is required." 
                                     ValidationGroup="RegisterUserValidationGroup">*</asp:RequiredFieldValidator>
                            </p>
                            <p>
                                <asp:Label ID="EmailLabel" runat="server" AssociatedControlID="Email">E-mail:</asp:Label>
                                <asp:TextBox ID="Email" runat="server" CssClass="textEntry" OnTextChanged="Email_TextChanged"></asp:TextBox>
                                <asp:RequiredFieldValidator ID="EmailRequired" runat="server" ControlToValidate="Email" 
                                     CssClass="failureNotification" ErrorMessage="E-mail is required." ToolTip="E-mail is required." 
                                     ValidationGroup="RegisterUserValidationGroup">*</asp:RequiredFieldValidator>
                            </p>
                            <p>
                                <asp:Label ID="PasswordLabel" runat="server" AssociatedControlID="Password">Password:</asp:Label>
                                <asp:TextBox ID="Password" runat="server" CssClass="passwordEntry" TextMode="Password" OnTextChanged="Password_TextChanged"></asp:TextBox>
                                <asp:RequiredFieldValidator ID="PasswordRequired" runat="server" ControlToValidate="Password" 
                                     CssClass="failureNotification" ErrorMessage="Password is required." ToolTip="Password is required." 
                                     ValidationGroup="RegisterUserValidationGroup">*</asp:RequiredFieldValidator>
                            </p>
                            <p>
                                <asp:Label ID="ConfirmPasswordLabel" runat="server" AssociatedControlID="ConfirmPassword">Confirm Password:</asp:Label>
                                <asp:TextBox ID="ConfirmPassword" runat="server" CssClass="passwordEntry" TextMode="Password" OnTextChanged="ConfirmPassword_TextChanged"></asp:TextBox>
                                <asp:RequiredFieldValidator ControlToValidate="ConfirmPassword" CssClass="failureNotification" Display="Dynamic" 
                                     ErrorMessage="Confirm Password is required." ID="ConfirmPasswordRequired" runat="server" 
                                     ToolTip="Confirm Password is required." ValidationGroup="RegisterUserValidationGroup">*</asp:RequiredFieldValidator>
                                <asp:CompareValidator ID="PasswordCompare" runat="server" ControlToCompare="Password" ControlToValidate="ConfirmPassword" 
                                     CssClass="failureNotification" Display="Dynamic" ErrorMessage="The Password and Confirmation Password must match."
                                     ValidationGroup="RegisterUserValidationGroup">*</asp:CompareValidator>
                            </p>
                        </fieldset>
                        <p class="submitButton">
                            <asp:Button ID="CreateUserButton" runat="server" CommandName="MoveNext" Text="Create User" 
                                 ValidationGroup="RegisterUserValidationGroup"/>
                        </p>
                    </div>
                </ContentTemplate>
                <CustomNavigationTemplate>
                </CustomNavigationTemplate>
            </asp:CreateUserWizardStep>
<asp:CompleteWizardStep runat="server"></asp:CompleteWizardStep>
        </WizardSteps>
    </asp:CreateUserWizard>
</asp:Content>

这里是Register.aspx.cs:我注释了不能编译的行…

Register.aspx.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Configuration;
using System.Data.SqlClient;
namespace LearnEF.Account
{
    public partial class Register : System.Web.UI.Page
    {
        protected void RegisterUser_CreatedUser(object sender, EventArgs e)
        {
            int userId = 0;
            string constr = ConfigurationManager.ConnectionStrings["ApplicationServices"].ConnectionString;
            using (SqlConnection con = new SqlConnection(constr))
            {
                using (SqlCommand cmd = new SqlCommand("Insert_User"))
                // note "Insert_User" is the name of the procedure that is 
                // stored in the `DB_Files` folder 
                // when we run this piece of code , the parameters @Username , @Password , @Email 
                // are passed to the procedure
                {
                    using (SqlDataAdapter sda = new SqlDataAdapter())
                    {
                        cmd.CommandType = CommandType.StoredProcedure;
                        cmd.Parameters.AddWithValue("@Username", UserName.Text.Trim());   // Error  1   The name 'UserName' does not exist in the current context   
                        cmd.Parameters.AddWithValue("@Password", Password.Text.Trim());   // Error  2   The name 'Password' does not exist in the current context
                        cmd.Parameters.AddWithValue("@Email", Email.Text.Trim());  // Error 3   The name 'Email' does not exist in the current context
                        cmd.Connection = con;
                        con.Open();
                        userId = Convert.ToInt32(cmd.ExecuteScalar());
                        con.Close();
                    }
                }
                string message = string.Empty;
                switch (userId)
                {
                    case -1:
                        message = "Username already exists.''nPlease choose a different username.";
                        break;
                    case -2:
                        message = "Supplied email address has already been used.";
                        break;
                    default:
                        message = "Registration successful.''nUser Id: " + userId.ToString();
                        break;
                }
                ClientScript.RegisterStartupScript(GetType(), "alert", "alert('" + message + "');", true);
            }
        }
        protected void ConfirmPassword_TextChanged(object sender, EventArgs e)
        {
        }
        protected void Email_TextChanged(object sender, EventArgs e)
        {
        }
        protected void UserName_TextChanged(object sender, EventArgs e)
        {
        }
        protected void Password_TextChanged(object sender, EventArgs e)
        {
        } // end 
    }

}

这里是设计器文件:

Register.aspx.designer.cs:

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated. 
// </auto-generated>
//------------------------------------------------------------------------------
namespace LearnEF.Account {

    public partial class Register {
        /// <summary>
        /// RegisterUser control.
        /// </summary>
        /// <remarks>
        /// Auto-generated field.
        /// To modify move field declaration from designer file to code-behind file.
        /// </remarks>
        protected global::System.Web.UI.WebControls.CreateUserWizard RegisterUser;
        /// <summary>
        /// RegisterUserWizardStep control.
        /// </summary>
        /// <remarks>
        /// Auto-generated field.
        /// To modify move field declaration from designer file to code-behind file.
        /// </remarks>
        protected global::System.Web.UI.WebControls.CreateUserWizardStep RegisterUserWizardStep;
    }
}

我甚至删除了文件Register.aspx.designer.cs并点击Convert to web application，但我得到了相同的Register.aspx.designer.cs。

请帮我解决这个问题

Thank you