从 ASP.NET Core 1.0 更新到 1.1 后的问题答案

【问题标题】：Issue after updating from ASP.NET Core 1.0 to 1.1从 ASP.NET Core 1.0 更新到 1.1 后的问题
【发布时间】：2017-11-29 19:18:24
【问题描述】：

在Official ASP.NET Article 之后，我从 ASP.NET Core 1.0 更新到 1.1。但是在编译我的 ASP.NET Core 项目时，我在 AccountController.cs 文件中收到以下错误：

错误：

The call is ambiguous between the following methods or properties: 'System.Security.Claims.PrincipalExtensions.FindFirstValue(System.Security.Claims.ClaimsPrincipal, string)' and 'System.Security.Claims.PrincipalExtensions.FindFirstValue(System.Security.Claims.ClaimsPrincipal, string)'

错误出现在以下操作方法末尾的 var email = info.Principal.FindFirstValue(ClaimTypes.Email); 行：

public async Task<IActionResult> ExternalLoginCallback(string returnUrl = null, string remoteError = null)
        {
            if (remoteError != null)
            {
                ModelState.AddModelError(string.Empty, $"Error from external provider: {remoteError}");
                return View(nameof(Login));
            }
            var info = await _signInManager.GetExternalLoginInfoAsync();
            if (info == null)
            {
                return RedirectToAction(nameof(Login));
            }

            // Sign in the user with this external login provider if the user already has a login.
            var result = await _signInManager.ExternalLoginSignInAsync(info.LoginProvider, info.ProviderKey, isPersistent: false);
            if (result.Succeeded)
            {
                _logger.LogInformation(5, "User logged in with {Name} provider.", info.LoginProvider);
                return RedirectToLocal(returnUrl);
            }
            if (result.RequiresTwoFactor)
            {
                return RedirectToAction(nameof(SendCode), new { ReturnUrl = returnUrl });
            }
            if (result.IsLockedOut)
            {
                return View("Lockout");
            }
            else
            {
                // If the user does not have an account, then ask the user to create an account.
                ViewData["ReturnUrl"] = returnUrl;
                ViewData["LoginProvider"] = info.LoginProvider;
                var email = info.Principal.FindFirstValue(ClaimTypes.Email);
                return View("ExternalLoginConfirmation", new ExternalLoginConfirmationViewModel { Email = email });
            }
        }

project.json：

{
  "userSecretsId": "aspnet-ABCTest-6af8ade3-87ff-4468-a9ce-8bb69c696ab8",

  "dependencies": {
    "Microsoft.NETCore.App": {
      "version": "1.1.0",
      "type": "platform"
    },
    "Microsoft.AspNet.Identity.EntityFramework": "3.0.0-rc1-final",
    "Microsoft.EntityFrameworkCore.SqlServer": "1.1.0",
    "Microsoft.EntityFrameworkCore.Tools": "1.1.0-preview4-final",
    "Microsoft.AspNetCore.Mvc": "1.1.0",
    "Microsoft.AspNetCore.Mvc.Core": "1.1.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.1.0",
    "Microsoft.EntityFrameworkCore.SqlServer.Design": "1.1.0",
    "Microsoft.AspNetCore.Authentication.Cookies": "1.1.0",
    "Microsoft.AspNetCore.Diagnostics": "1.1.0",
    "Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore": "1.1.0",
    "Microsoft.AspNetCore.Identity": "1.1.0",
    "Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.1.0",
    "Microsoft.AspNetCore.Razor.Tools": "1.1.0-preview4-final",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.1.0",
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.1.0-preview4-final",
    "Microsoft.AspNetCore.StaticFiles": "1.1.0",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.1.0",
    "Microsoft.Extensions.Configuration.Json": "1.1.0",
    "Microsoft.Extensions.Configuration.UserSecrets": "1.1.0",
    "Microsoft.Extensions.Logging": "1.1.0",
    "Microsoft.Extensions.Logging.Console": "1.1.0",
    "Microsoft.Extensions.Logging.Debug": "1.1.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.1.0",
    "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.1.0",
    "Microsoft.VisualStudio.Web.CodeGeneration.Tools": "1.1.0-preview4-final",
    "Microsoft.VisualStudio.Web.CodeGenerators.Mvc": "1.1.0-preview4-final"  },

  "tools": {
    "BundlerMinifier.Core": "2.0.238"  },

  "frameworks": {
    "netcoreapp1.1": {
      "imports": [
        "dotnet5.6",
        "portable-net45+win8"
      ]
    }
  },

  "buildOptions": {
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  },

  "runtimeOptions": {
    "configProperties": {
      "System.GC.Server": true
    }
  },

  "publishOptions": {
    "include": [
      "wwwroot",
      "Views",
      "Areas/**/Views",
      "appsettings.json",
      "web.config"
    ]
  },

  "scripts": {
    "prepublish": [ "bower install", "dotnet bundle" ],
    "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  }
}

【问题讨论】：

可能是您正在使用的 pre-RTM 身份包。你能从Microsoft.AspNet.Identity.EntityFramework切换到"Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.1.0"看看是否能解决这个问题？
@Pranav 但是，正如您在我在上面发布的 project.json 文件中注意到的那样，"Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.1.0" 已经存在。
在这种情况下，请尝试删除 "Microsoft.AspNet.Identity.EntityFramework": "3.0.0-rc1-final"。这是您的依赖项中的第一项。
@Pranav 你的最后一个建议奏效了（谢谢）。您可能希望将您的评论更改为包含一些有用详细信息的回复（为了其他用户的利益），我会将其标记为答案。

标签： visual-studio-2015 asp.net-core-mvc

【解决方案1】：

尝试从您的依赖项中删除 "Microsoft.AspNet.Identity.EntityFramework": "3.0.0-rc1-final"。混合来自不同版本的包 - 在这种情况下，pre-RTM 和 1.1.0 通常是导致这种 API 歧义的原因。

【讨论】：