在.net中使用默认表单填充值

我有一个IdentityUser模型

我有一个管理视图与3部分(每一个有一个视图模型和控制器)，我想在这个视图上输入，并看到与模型的数据填充的表单。

ApplicationUser: IdentityUser (Model of my user)

using Microsoft.AspNet.Identity.EntityFramework;
using System;
namespace MTGWeb.Models
{
    // You can add profile data for the user by adding more properties to your ApplicationUser class, please visit http://go.microsoft.com/fwlink/?LinkID=317594 to learn more.
    public class ApplicationUser : IdentityUser
    {
        public String Pais;
        public String Email;
        public DateTime UltimoLogin;
        public DateTime FechaRegistro;
        public String Tipo;
        public Boolean Activado;
    }
    public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
    {
        public ApplicationDbContext()
            : base("DefaultConnection")
        {
        }
    }
}

Manage (Main View)

@using MTGWeb.Models;
@using Microsoft.AspNet.Identity;
@{
    ViewBag.Title = "Administrar cuenta";
}
<h2>@ViewBag.Title.</h2>
<p class="text-success">@ViewBag.StatusMessage</p>
<div class="row">
    <div class="col-md-12">
        <p>Ha iniciado sesión como <strong>@User.Identity.GetUserName()</strong>.</p>
        @Html.Partial("_ChangePasswordPartial")
        @Html.Partial("_ChangeEmailPartial")
        @Html.Partial("_OtherFieldsPartial")
    </div>
</div>
@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

_ChangeEmailPartial

@using Microsoft.AspNet.Identity
@model MTGWeb.Models.ManageUserViewModelEmailChange
@using (Html.BeginForm("ManageEmail", "Account", FormMethod.Post, new { @class = "form-horizontal", role = "form" }))
{
    @Html.AntiForgeryToken()
    <h4>Formulario para cambiar email</h4>
    <hr />
    @Html.ValidationSummary()
    <div class="form-group">
        @Html.LabelFor(m => m.OldEmail, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.TextBoxFor(m => m.OldEmail, new { @class = "form-control", Value = Model.OldEmail})
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(m => m.NewEmail, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.TextBoxFor(m => m.NewEmail, new { @class = "form-control" }) 
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(m => m.ConfirmEmail, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.TextBoxFor(m => m.ConfirmEmail, new { @class = "form-control" })
        </div>
    </div>
    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="Cambiar email" class="btn btn-default" />
        </div>
    </div>
}

Controller - ManageEmail

// Cambia el email
// POST: /Account/ManageEmail
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> ManageEmail(ManageUserViewModelEmailChange model)
{
    ViewBag.ReturnUrl = Url.Action("Manage");

    var user = await UserManager.FindByNameAsync(User.Identity.Name);
    if (ModelState.IsValid)//Si no hay errores en la validación que hace la clase (Datatype, length, required, etc..)
    {
        if (model.OldEmail.Equals(model.NewEmail) && model.OldEmail.Equals(user.Email))
        {
            user.Email = model.NewEmail;
            IdentityResult success = await UserManager.UpdateAsync(user);
            if (success.Succeeded)
            {
                return RedirectToAction("Manage", new { Message = ManageMessageId.ChangeEmailSuccess });
            }
        }
    }
    //Si el modelo no es válido o no el cambio no ha tenido exito
    return View(model);
}

对于其他部分，我还有2个控制器，但这对于示例很有用。这些Model.OldEmail是空的，导致Nullreference错误，我要在哪里填充它?我猜这个必须填入AccountController/Manage，但是…我怎么把它放到偏导数里呢?

我是MVC和。net的新手，我曾经使用Java工作，我被困在这个(是一个测试项目的目的)

  @Html.Partial("_ChangePasswordPartial",Model.ChangePAsswordViewModel)

 @model MTGWeb.Models.ManageViewModel

public class ManageViewModel
{
    public ChangePasswordViewModel ChangePasswordViewModel{get;set;}
    public NextViewModel NextViewModel{get;set;}
    public AnotherViewModel NextViewModel{get;set;}
}