IdentityUser的外鍵引用顯示NULL值（EF6/ASP.NET MVC 5）

Question

我想弄清楚爲什麼我的模型表的UserId列引用我的AspNetUsers表的主鍵「Id」（IdentityUser類IdentityModel ）只顯示空值當我'創建（）'條目。

這裏是我的兩個）的代碼創建（在我的控制器類的ActionResult方法：

[Authorize] 
    public ActionResult Create() 
    { 
     ViewBag.UserId = new SelectList(db.Users, "Id", "Fullname"); 
     return View(); 
    } 

    // POST: Expenses/Create 

    [HttpPost] 
    [ValidateAntiForgeryToken] 
    [Authorize] 
    public ActionResult Create([Bind(Include = "ID,Category,Description,GrossAmount,TaxAmount,NetAmount,Mileage,MileageRate,DateSubmitted,ExpenseDate,UserId")] Expense expense) 
    { 
     if (ModelState.IsValid) 
     { 
      expense.UserId = HttpContext.Current.User.Identity.Name; 
      db.Expenses.Add(expense); 
      db.SaveChanges(); 
      return RedirectToAction("Index"); 
     } 

     ViewBag.UserId = new SelectList(db.Users, "Id", "Fullname", expense.UserId); 
     return View(expense); 
    } 

這裏是我創建視圖代碼：

@{ 
    ViewBag.Title = "Create"; 
    Layout = "~/Views/Shared/_Layout.cshtml"; 

    DateTime today = DateTime.Today; 
    string formattedDate = today.ToString("MM/dd/yyyy"); 
} 

<h2>Create</h2> 

@using (Html.BeginForm()) 
{ 
    @Html.AntiForgeryToken() 

    <div class="form-horizontal"> 
     <h4>Expense</h4> 
     <hr /> 
     @Html.ValidationSummary(true, "", new { @class = "text-danger" }) 

     <div class="form-group"> 
      @Html.LabelFor(model => model.UserId, htmlAttributes: new { @Value = user, @class = "control-label col-md-2" }) 
      <div class="col-md-10"> 
       @Html.EditorFor(model => model.UserId, new { htmlAttributes = new { @class = "form-control" } }) 
       @Html.ValidationMessageFor(model => model.UserId, "", new { @class = "text-danger" }) 
      </div> 
     </div> 

     <div class="form-group"> 
      @Html.LabelFor(model => model.DateSubmitted, htmlAttributes: new { @class = "control-label col-md-2" }) 
      <div class="col-md-10"> 
       @Html.EditorFor(model => model.DateSubmitted, new { htmlAttributes = new { @Value = formattedDate, @class = "form-control" } }) 
       @Html.ValidationMessageFor(model => model.DateSubmitted, "", new { @class = "text-danger" }) 
      </div> 
     </div> 

     <div class="form-group"> 
      @Html.LabelFor(model => model.ExpenseDate, htmlAttributes: new { @Value = @formattedDate, @class = "control-label col-md-2" }) 
      <div class="col-md-10"> 
       @Html.EditorFor(model => model.ExpenseDate, new { htmlAttributes = new { @class = "form-control" } }) 
       @Html.ValidationMessageFor(model => model.ExpenseDate, "", new { @class = "text-danger" }) 
      </div> 
     </div> 

     <div class="form-group"> 
      @Html.LabelFor(model => model.Category, htmlAttributes: new { @class = "control-label col-md-2" }) 
      <div class="col-md-10"> 
       @Html.DropDownListFor(model => model.Category, new SelectList(
        new List<String>{ 
         "Meals & Entertainment", 
         "Home Office", 
         "Travel", 
         "Phone", 
         "Auto - Mileage", 
         "Auto - Gas", 
         "Auto - Lease", 
         "Association Dues", 
         "Insurance Premium", 
         "Capital Assets", 
         "Trade Show & Promo", 
         "Pan Experience", 
         "Other" 
        }), new { @class = "form-control" }) 

       @Html.ValidationMessageFor(model => model.Category, "", new { @class = "text-danger" }) 
      </div> 
     </div> 

     <div class="form-group"> 
      @Html.LabelFor(model => model.Description, htmlAttributes: new { @class = "control-label col-md-2" }) 
      <div class="col-md-10"> 
       @Html.EditorFor(model => model.Description, new { htmlAttributes = new { @class = "form-control" } }) 
       @Html.ValidationMessageFor(model => model.Description, "", new { @class = "text-danger" }) 
      </div> 
     </div> 

     <div class="form-group"> 
      @Html.LabelFor(model => model.Mileage, htmlAttributes: new { @class = "control-label col-md-2" }) 
      <div class="col-md-10"> 
       @Html.EditorFor(model => model.Mileage, new { htmlAttributes = new { @class = "form-control" } }) 
       @Html.ValidationMessageFor(model => model.Mileage, "", new { @class = "text-danger" }) 
      </div> 
     </div> 

     <div class="form-group"> 
      @Html.LabelFor(model => model.MileageRate, htmlAttributes: new { @class = "control-label col-md-2" }) 
      <div class="col-md-10"> 
       @Html.EditorFor(model => model.MileageRate, new { htmlAttributes = new { @class = "form-control" } }) 
       @Html.ValidationMessageFor(model => model.MileageRate, "", new { @class = "text-danger" }) 
      </div> 
     </div> 

     <div class="form-group"> 
      @Html.LabelFor(model => model.GrossAmount, htmlAttributes: new { @class = "control-label col-md-2" }) 
      <div class="col-md-10"> 
       @Html.EditorFor(model => model.GrossAmount, new { htmlAttributes = new { @class = "form-control" } }) 
       @Html.ValidationMessageFor(model => model.GrossAmount, "", new { @class = "text-danger" }) 
      </div> 
     </div> 

     <div class="form-group"> 
      @Html.LabelFor(model => model.TaxAmount, htmlAttributes: new { @class = "control-label col-md-2" }) 
      <div class="col-md-10"> 
       @Html.EditorFor(model => model.TaxAmount, new { htmlAttributes = new { @class = "form-control" } }) 
       @Html.ValidationMessageFor(model => model.TaxAmount, "", new { @class = "text-danger" }) 
      </div> 
     </div> 

     <div class="form-group"> 
      @Html.LabelFor(model => model.NetAmount, htmlAttributes: new { @class = "control-label col-md-2" }) 
      <div class="col-md-10"> 
       @Html.EditorFor(model => model.NetAmount, new { htmlAttributes = new { @class = "form-control" } }) 
       @Html.ValidationMessageFor(model => model.NetAmount, "", new { @class = "text-danger" }) 
      </div> 
     </div> 


     <div class="form-group"> 
      <div class="col-md-offset-2 col-md-10"> 
       <input type="submit" value="Create" class="btn btn-default" /> 
      </div> 
     </div> 
    </div> 
} 

<div> 
    @Html.ActionLink("Back to List", "Index") 
</div> 

@section scripts { 

    <script type="text/javascript"> 
     var province = 'bc'; 
     var grossAmount = document.getElementById('GrossAmount').value; 

     $(function() { 

      $('#ExpenseDate').datetimepicker({ 

       defaultDate: '@formattedDate', 

       format: 'L', 

       showClose: true, 

       showClear: true, 

       toolbarPlacement: 'top' 

      }); 

     }); 

     $('#DateSubmitted').prop('readonly', true); 
     $('#Mileage').prop('disabled', true); 
     $('#MileageRate').prop('disabled', true); 

     $(function() 
     { 
      $('#Category').on('change',function() 
      { 
       if ($(this).val() == 'Auto - Mileage') 
       { 
        $('#Mileage').prop('disabled', false); 
        $('#MileageRate').prop('disabled', false); 
       } 
       else 
       { 
        $('#Mileage').prop('disabled', true); 
        $('#MileageRate').prop('disabled', true); 
       } 

      } 

      ) 
     }) 


    </script> 
} 

如果你想看看我的模特班，你可以去這個帖子：

• How To Restrict User Entries Only to that Sepcific User in EF 6/ASP.NET MVC 5

---

UPDATE：

感謝史蒂夫格林爲把我在正確的軌道上，並幫我更新的Create（）方法是：

public ActionResult Create() 
    { 
     ViewBag.UserId = new SelectList(db.Users, "Id", "Fullname"); 
     return View(); 
    } 

    // POST: Expenses/Create 

    [HttpPost] 
    [ValidateAntiForgeryToken] 
    [Authorize] 
    public ActionResult Create([Bind(Include = "ExpenseId,Category,Description,GrossAmount,TaxAmount,NetAmount,Mileage,MileageRate,DateSubmitted,ExpenseDate,UserId")] Expense expense) 
    { 
     if (ModelState.IsValid) 
     { 
      expense.UserId = System.Web.HttpContext.Current.User.Identity.Name; 
      db.Expenses.Add(expense); 
      db.SaveChanges(); 
      return RedirectToAction("Index"); 
     } 

     ViewBag.UserId = new SelectList(db.Users, "Id", "Fullname", expense.UserId); 

     foreach (ModelState modelState in ViewData.ModelState.Values) 
     { 
      foreach (ModelError error in modelState.Errors) 
      { 
       Response.Write(error); 
      } 
     } 
     Response.End(); 
     return View(expense); 

    } 

我現在沒有遇到任何重大錯誤，但是，現在ModelState.IsValid正在返回False，並且我輸入到Create.cshtml中的數據不是正在提交。

我添加一段代碼在Create（）方法捉ModelState.Errors和它打印錯誤：System.Web.Mvc.ModelError。我也在Create（）之前設置了一個斷點，當我檢查UserId的值時，我得到「null」。

---

最後更新：

我添加了一個字段，用戶ID的Create.cshtml看法，現在我得到的錯誤：INSERT語句衝突與外鍵約束「FK_dbo。 Expenses_dbo.AspNetUsers_ApplicationUser_Id」。衝突發生在數據庫「PacificPetExpenses」，表「dbo.AspNetUsers」，列'Id'。

要解決這個問題，我在我的控制器中修改了一些東西（請參閱下面的答案）。

謝謝。

Answer 1

裏面的內我的控制器的Create（）方法，我有行：

expense.UserId = HttpContext.Current.User.Identity.Name; 

我成立了一個破發點和斷點就行了，它顯示了正確的UserId;但是，在執行完該行後，它會顯示用戶的電子郵件地址。

爲了解決這個問題我試圖改變上面的一行：

expense.UserId = System.Web.HttpContext.Current.User.Identity.GetUserId(); 

和支出雙雙被沒有錯誤提交，並顯示在它應該顯示的用戶提交的費用清單視圖！

Answer 2

如果不使用視圖的用戶ID，只需將它添加之前：

if (ModelState.IsValid) 
    { 
     expense.UserId = HttpContext.Current.User.Identity.Name; // or whatever 
     db.Expenses.Add(expense); 
     db.SaveChanges(); 
     return RedirectToAction("Index"); 
    } 

另一種常見的模式是添加一個隱藏字段的用戶名：

@using (Html.BeginForm()) 
{ 
    @Html.AntiForgeryToken() 
    @Html.HiddenFor(model => model.UserId) <-- now it will post back 
    ... 

如果你想有一個下拉列表的用戶，這樣做：

[Authorize] 
public ActionResult Create() 
{ 
    ViewBag.UserList = new SelectList(db.Users, "Id", "Fullname"); 
    return View(); 
} 

然後在你的視圖中添加一個下拉列表的用戶：

<div class="form-group"> 
     @Html.LabelFor(model => model.UserId, htmlAttributes: new { @class = "control-label col-md-2" }) 
     <div class="col-md-10"> 
      @Html.DropDownListFor(model => model.UserId, Model.UserList, new { @class = "form-control" }) 
      @Html.ValidationMessageFor(model => model.UserId, "", new { @class = "text-danger" }) 
     </div> 
    </div>