.Net Standard 2.0 中的 ApplicationDbContext.OnModelCreating() 有 MissingMethodException

问题描述

这是我在 " 中发布的问题之一;发现不同版本之间存在冲突"OR System.MissingMethodException 使用aspnetcore.identity时，不过我想用一个小例子单独说明一下:

this is one of the problems that I issued in "Found conflicts between different versions" OR System.MissingMethodException when using aspnetcore.identity, but I wanted to explain it separately with a small example:

设置:

1. .Net 标准 2.0 库
2. .Net Framework 4.7.2 WebForms 应用程序

.Net 标准库有这个代码:

The .Net standard Library has this Code:

 public class Class1
    {
        public static void doStuff()
        {
            var optionsBuilder = new DbContextOptionsBuilder<ApplicationDbContext>();
            optionsBuilder.UseSqlServer("MyConnectionString");

            var userStore = new UserStore<ApplicationUser, MyRole, ApplicationDbContext, Guid>(
                new ApplicationDbContext(optionsBuilder.Options)
                ); // the userStore.Users property shows already the exception in the debugger

            AspNetUserManager<ApplicationUser> userManager = new AspNetUserManager<ApplicationUser>(
                userStore,
                null,
                new PasswordHasher<ApplicationUser>(),
                new List<UserValidator<ApplicationUser>>() { new UserValidator<ApplicationUser>() },
                null,
                null,
                null,
                null,
                null
                );

            var x = userManager.Users; // exception throw (see next code snipped)
        }
    }

    public class ApplicationDbContext : IdentityDbContext<ApplicationUser, MyRole, Guid>
    {
        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
            : base(options)
        {

        }

        protected override void OnModelCreating(ModelBuilder builder)
        {
            base.OnModelCreating(builder); // after userManager.Users is called the exception is thrown here
        }
    }

在 WebForms-Project 中:

And in the WebForms-Project just:

public partial class _Default : Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            Class1.doStuff();
        }
    }

例外:System.MissingMethodException: 'Methode nicht gefunden: "Microsoft.EntityFrameworkCore.Metadata.Builders.IndexBuilder Microsoft.EntityFrameworkCore.Metadata.Builders.EntityTypeBuilder1.HasIndex(System.Linq.Expressions.Expression1>)".'

Exception:System.MissingMethodException: 'Methode nicht gefunden: "Microsoft.EntityFrameworkCore.Metadata.Builders.IndexBuilder Microsoft.EntityFrameworkCore.Metadata.Builders.EntityTypeBuilder1.HasIndex(System.Linq.Expressions.Expression1>)".'

.Net Standard 2.0 项目的配置:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Identity" Version="2.2.0" />
    <PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="2.2.0" />
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="3.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="3.1.1" />
    <PackageReference Include="Microsoft.Extensions.Identity.Stores" Version="3.1.1" />
  </ItemGroup>

</Project>

参考:https://github.com/dotnet/aspnetcore/issues/8467 他们说更新到Microsoft.AspNetCore.Identity"3.x，但我不能这样做，因为它与 .Net Standard 2.0 项目不兼容，我需要它用于 WebForms 项目.

References:https://github.com/dotnet/aspnetcore/issues/8467 Here they say to update to "Microsoft.AspNetCore.Identity" 3.x, but I cannot do that because its not compatible with the .Net Standard 2.0 project and I need that for the WebForms Project.

所以我的问题是，如果有人知道一种以不同方式生成用户管理器的解决方法......我需要使用 aspnetcore-identity(数据库等)来获取和设置用户(并验证).已经迁移)

So my question would be if someone knows a workaround to generate an Usermanager in a different way... I need to Get and Set Users (and validate) using aspnetcore-identity (database etc. is already migrated)

推荐答案

所以，我有一个解决我的问题的方法:

So, I have a solution for my problem:

使用 Microsoft.EntityFrameworkCore.SqlServer 2.2.6 版(不 3.1.1，即使它应该与 .net 标准 2.0 一起使用...)

use Microsoft.EntityFrameworkCore.SqlServer version 2.2.6 (NOT 3.1.1 even though its supposed to work with .net standard 2.0...)

以及一系列的

• 删除 nuget 包
• 清除 nuget 缓存
• 删除本地计算机上的 nuget 包(在 C:/../Users/.../.nuget 文件夹中)
• 将 nuget 管理格式更改为PackageReference"
• 经常哭
• 重新安装所有东西并处理警告有帮助

(我不能说版本冲突到底是什么问题)

(I cant say what exactly the issue was regarding the version-conflicts)

这篇关于.Net Standard 2.0 中的 ApplicationDbContext.OnModelCreating() 有 MissingMethodException的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！