在 ASP.NET MVC 中使用上下文编辑 ASP.NET 用户后更新数据库答案

【问题标题】：Updating the database after editing the ASP.NET User using context in ASP.NET MVC在 ASP.NET MVC 中使用上下文编辑 ASP.NET 用户后更新数据库
【发布时间】：2019-12-06 15:59:28
【问题描述】：

我正在努力将新数据保存到数据库中，因为我找不到合适的 ApplicationDbContext 方法。首先，让我向您展示导致此问题的步骤。下面的方法展示了如何从 Db 中获取必要的字段以填充 Edit 视图中的字段。

 public ActionResult UsersWithRoles()
    {
        var usersWithRoles = (from user in context.Users
                              select new
                              {
                                  UserId = user.Id,
                                  Username = user.UserName,
                                  Email = user.Email,
                                  RoleNames = (from userRole in user.Roles
                                               join role in context.Roles on userRole.RoleId
                                               equals role.Id
                                               select role.Name).ToList()
                              }).ToList().Select(p => new UserViewModels()

                              {
                                  UserId = p.UserId,
                                  Username = p.Username,
                                  Email = p.Email,
                                  Role = string.Join(",", p.RoleNames)
                              });


        return View(usersWithRoles);
    }

这很好用，视图如下所示：

没错。现在，如果我点击“保存”，这就是应该将新数据传递到数据库的方法：

 [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> Edit(UserViewModels user)
    {
        if (ModelState.IsValid)
        {
            context.Update(user);
            await context.SaveChangesAsync();
            return null;
        }
        return null;

    }

在我遵循的教程中，使用了context.Update - 但是，在我的例子中，它说ApplicationDbContext 没有一个名为Update 的方法。此外，返回 RedirectToAction 不起作用，因为

它不能将 System.Web.Mvc.RedirectToRouteResult 转换为 Microsoft.AspNetCore.Mvc.IActionResult

后一种方法应该如何写才能正常工作？

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    <Content Include="Scripts\src\utils\runModifiers.js" />
    <Content Include="Scripts\src\utils\setAttributes.js" />
    <Content Include="Scripts\src\utils\setStyles.js" />
    <Content Include="Scripts\src\utils\setupEventListeners.js" />
    <Content Include="Scripts\umd\popper-utils.js" />
    <Content Include="Scripts\umd\popper-utils.min.js" />
    <Content Include="Scripts\umd\popper.js" />
    <Content Include="Scripts\umd\popper.min.js" />
    <Content Include="Web.config" />
    <Content Include="Web.Debug.config">
      <DependentUpon>Web.config</DependentUpon>
    </Content>
    <Content Include="Web.Release.config">
      <DependentUpon>Web.config</DependentUpon>
    </Content>
    <Content Include="Views\Web.config" />
    <Content Include="Views\_ViewStart.cshtml" />
    <Content Include="Views\Shared\Error.cshtml" />
    <Content Include="Views\Shared\_Layout.cshtml" />
    <Content Include="Views\Home\About.cshtml" />
    <Content Include="Views\Home\Contact.cshtml" />
    <Content Include="Views\Home\Index.cshtml" />
    <Content Include="Views\Account\_ExternalLoginsListPartial.cshtml" />
    <Content Include="Views\Account\ConfirmEmail.cshtml" />
    <Content Include="Views\Account\ExternalLoginConfirmation.cshtml" />
    <Content Include="Views\Account\ExternalLoginFailure.cshtml" />
    <Content Include="Views\Account\ForgotPassword.cshtml" />
    <Content Include="Views\Account\ForgotPasswordConfirmation.cshtml" />
    <Content Include="Views\Account\Login.cshtml" />
    <Content Include="Views\Account\Register.cshtml" />
    <Content Include="Views\Account\ResetPassword.cshtml" />
    <Content Include="Views\Account\ResetPasswordConfirmation.cshtml" />
    <Content Include="Views\Account\SendCode.cshtml" />
    <Content Include="Views\Account\VerifyCode.cshtml" />
    <Content Include="Views\Manage\AddPhoneNumber.cshtml" />
    <Content Include="Views\Manage\ChangePassword.cshtml" />
    <Content Include="Views\Manage\Index.cshtml" />
    <Content Include="Views\Manage\ManageLogins.cshtml" />
    <Content Include="Views\Manage\SetPassword.cshtml" />
    <Content Include="Views\Manage\VerifyPhoneNumber.cshtml" />
    <Content Include="Views\Shared\Lockout.cshtml" />
    <Content Include="Views\Shared\_LoginPartial.cshtml" />
    <Content Include="Scripts\umd\popper.min.js.map" />
    <Content Include="Scripts\umd\popper.js.map" />
    <Content Include="Scripts\umd\popper.js.flow" />
    <Content Include="Scripts\umd\popper-utils.min.js.map" />
    <Content Include="Scripts\umd\popper-utils.js.map" />
    <Content Include="Scripts\README.md" />
    <Content Include="Scripts\popper.min.js.map" />
    <Content Include="Scripts\popper.js.map" />
    <Content Include="Scripts\popper-utils.min.js.map" />
    <Content Include="Scripts\popper-utils.js.map" />
    <Content Include="Views\ManageUsers\UsersWithRoles.cshtml" />
    <Content Include="Views\ManageUsers\Edit.cshtml" />
    <Content Include="Views\ManageUsers\CreateUser.cshtml" />
  </ItemGroup>
  <ItemGroup>
    <Folder Include="App_Data\" />
  </ItemGroup>
  <ItemGroup>

【问题讨论】：

上下文变量的类型是什么？ IdentityDbContext 还是 DbContext？
你用的是什么版本的asp.net？
是 IdentityDbContext。至于版本，我想是2.2.6
我现在正忙着用一个很好的例子来回答。但是你可以按照特拉维斯的回答。如果有任何问题，我可以稍后提供答案。
@LuttiCoelho 我按照特拉维斯的回答，但找不到办法。请检查我在他的帖子上的回复，也许给我一些解决问题的提示。

标签： c# asp.net asp.net-mvc

【解决方案1】：

您正在将 ORM 生成的用户模型解析为自定义视图模型，要求用户对其进行编辑，然后期望您的数据库上下文自动将其转换回来并保存。您的数据库上下文没有关于如何将视图模型转换回模型的自动概念。它只是一个抽象类映射到您的数据库。您必须自己明确地执行此操作或探索诸如自动映射器之类的选项以将两个类映射在一起。

关于高级对象的快速未测试示例

[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Edit(UserViewModels user)
{
    if (ModelState.IsValid)
    {

      var u = context.Users.where(a => a.Id == UserId).FirstOrDefault();
      if(u != null)
      {
        u.UserName = user.UserName
        so on.....
        await context.SaveChangesAsync();
        return RedirectToAction("CompleteActionName");
      }

        return RedirectToAction("UserNotFound", user);
    }
    return View(user);

}

【讨论】：

非常感谢您的示例。很抱歉我不能早点回来回答。我有两个问题 - 首先是如何访问 AspNetUserRoles 表以更改某个用户的角色？其次，我仍然遇到 RedirectToAction 和 View 方法的问题，因为它们无法从 Web.Mvc.RedirectToRouteResult 转换为 AspNetCore.Mvc.IActionResult。请给我一些解决这两个问题的建议好吗？
上述语句的更新：我删除了 Async 的东西并修复了 RedirectToAction 部分。但是，我在传递更新后的角色时仍然遇到问题。

【解决方案2】：

第一个问题，就像@TravisActon 所说的那样，是您期望 EF 自动将 UserViewModels 类转换为 IdentityUser。你可以完全按照特拉维斯在他的回答中解释的那样做。我只是想给你第二个选择。使用UserManager 类，它为您提供了许多处理用户和角色的功能。

如果您将 Asp.Net Framework 与 OWIN 一起使用很确定。

首先在你的控制器上添加这个：

using Microsoft.AspNet.Identity.Owin;

然后对您的方法进行一些更改：

[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Edit(UserViewModels userViewModel)
{
    if (!ModelState.IsValid)
        return View(userViewModel);

    // Get UserManager from OwinContext needs "using Microsoft.AspNet.Identity.Owin;"
    var userManager = HttpContext.GetOwinContext().GetUserManager<ApplicationUserManager>();

    var appUser = await userManager.FindByIdAsync(userViewModel.UserId);
    if (appUser == null)
        return await Task.Run<ActionResult>(() => RedirectToAction("UserNotFound", userViewModel));

    appUser.UserName = userViewModel.Username;
    appUser.Email = userViewModel.Email;

    // Updates the user information with UserManager
    await userManager.UpdateAsync(appUser);

    // Get all roles from user.
    var currentUserRoles = await userManager.GetRolesAsync(appUser.Id);

    // Remove all current roles fro this user. You can skip it if you don't need it.
    var removeCurrentRolesResult = await userManager.RemoveFromRolesAsync(appUser.Id, currentUserRoles.ToArray());

    // Verify if any error occours
    if(!removeCurrentRolesResult.Succeeded)
    {
        // Add errors to ModelState.
        removeCurrentRolesResult.Errors.ToList().ForEach(error => ModelState.AddModelError("Role", error));

        return View(userViewModel);
    }

    // get userRoles from text to an array of string;
    var newRoles = userViewModel.Role.Split(',').Select(_ => _.Trim());

    // Adds user to the new role
    var addRoleResult = await userManager.AddToRolesAsync(appUser.Id, newRoles.ToArray());

    if (!addRoleResult.Succeeded)
    {
          // handle errors like removeCurrentRolesResult
          return View(userViewModel);
    }

    return await Task.Run<ActionResult>(() => RedirectToAction("UsersWithRoles"));
}

您使用 Asp.Net Core 2+ 的情况

[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Edit([FromService] UserManager userManager, UserViewModels userViewModel)
{
    if (!ModelState.IsValid)
        return View(userViewModel);

    var userModel = await userManager.FindByIdAsync(userViewModel.Id);
    if(userModel == null)
    {
        return await Task.Run<ActionResult>(() => RedirectToAction("UserNotFound", userViewModel));
    }

    // Updates the user information with UserManager
    userManager.SetUserNameAsync(userModel, userViewModel.UserName);
    userManager.SetEmailAsync(userModel, userViewModel.Email);

    // Get all roles from user.
    var currentUserRoles = await userManager.GetRolesAsync(userModel);

    // Remove all current roles fro this user. You can skip it if you don't need it.
    var removeCurrentRolesResult = await userManager.RemoveFromRolesAsync(appUser, currentUserRoles);

    // Verify if any error occours
    if(!removeCurrentRolesResult.Succeeded)
    {
        // Add errors to ModelState.
        removeCurrentRolesResult.Errors.ToList().ForEach(t => ModelState.AddModelError("Role", t.Description));

        return View(userViewModel);
    }

    // get userRoles from text to an array of string;
    var newRoles = userViewModel.Roles.Split(',').Select(_ => _.Trim());

    // Adds user to the new role
    var addRoleResult = await _userManager.AddToRolesAsync(userModel, newRoles);

    if (!addRoleResult.Succeeded)
    {
      // handle errors like removeCurrentRolesResult
      return View(userViewModel);
    }


    // Return redirect to action object without need to remove async from method.
    return await Task.Run<ActionResult>(() => RedirectToAction("UserNotFound", userModel));
}

关于重定向的第二个问题是因为RedirectToAction 是IActionResult，而您的方法返回Task<IActionResult>，因此要解决此问题，您需要将方法的返回类型更改为IActionResult 或调用RedirectToAction进入async 电话。像这样：

return await Task.Run<ActionResult>(() => RedirectToAction("ActionName", model));

【讨论】：

感谢您的回答。不幸的是，我有几个问题：第一个是找不到[FromService] 属性。它是只能在 AspNetCore 中使用的东西吗？其次，return await Task.Run<IActionResult>(() => RedirectToAction("UserNotFound", userViewModel)); 行返回错误cannot convert lambda expression to type because it is not a delegate type。此外，它也找不到方法SetUserNameAsync，而SetEmailAsync 有效。最后，没有找到变量appUser。它究竟应该是什么？感谢您对此问题的任何帮助！
[FromService] 仅适用于 Asp.net 核心。正如您所说，您使用的是 2.2.6 版本，我想那是您的 asp.net 核心版本。
appUser 是我的错误。它应该是用户模型。我会在我的答案上修正它
@Questieme 我已经用 Asp.Net Framework 版本的解决方案更新了我的答案。我很确定这会解决您的问题。
请保留解决堆栈溢出问题所需的所有代码。我们会以这种方式帮助更多的人。