为什么会出现这种违反类型约束？ [英] Why does this violate the type constraint?

问题描述

我想自定义ASP.NET身份3，以便它使用整数键：

I'm trying to customise ASP.NET Identity 3 so that it uses integer keys:

public class ApplicationUserLogin : IdentityUserLogin<int> { }
public class ApplicationUserRole : IdentityUserRole<int> { }
public class ApplicationUserClaim : IdentityUserClaim<int> { }

public sealed class ApplicationRole : IdentityRole<int>
{
  public ApplicationRole() { }
  public ApplicationRole(string name) { Name = name; }
}

public class ApplicationUserStore : UserStore<ApplicationUser, ApplicationRole, ApplicationDbContext, int>
{
  public ApplicationUserStore(ApplicationDbContext context) : base(context) { }
}

public class ApplicationRoleStore : RoleStore<ApplicationRole, ApplicationDbContext, int>
{
  public ApplicationRoleStore(ApplicationDbContext context) : base(context) { }
}

public class ApplicationUser : IdentityUser<int>
{
}

public sealed class ApplicationDbContext : IdentityDbContext<ApplicationUser, ApplicationRole, int>
{
  private static bool _created;

  public ApplicationDbContext()
  {
    // Create the database and schema if it doesn't exist
    if (!_created) {
      Database.AsRelational().Create();
      Database.AsRelational().CreateTables();
      _created = true;
    }
  }
}

这编译好的，但随后引发运行时错误：

This compiles okay, but then throws a runtime error:

System.TypeLoadException

GenericArguments [0]，'TeacherPlanner.Models.ApplicationUser'，在'Microsoft.AspNet.Identity.EntityFramework.UserStore`4 [TUSER，TRole，TContext，TKEY的]'违反类型参数TUSER'的约束。

GenericArguments[0], 'TeacherPlanner.Models.ApplicationUser', on 'Microsoft.AspNet.Identity.EntityFramework.UserStore`4[TUser,TRole,TContext,TKey]' violates the constraint of type parameter 'TUser'.

为 UserStore 签名是：

public class UserStore<TUser, TRole, TContext, TKey>
where TUser : Microsoft.AspNet.Identity.EntityFramework.IdentityUser<TKey>
where TRole : Microsoft.AspNet.Identity.EntityFramework.IdentityRole<TKey>
where TContext : Microsoft.Data.Entity.DbContext
where TKey : System.IEquatable<TKey>

ApplicationUser 是precisely一个 IdentityUser＆LT; INT＆GT; 。难道这不是什么它找？

ApplicationUser is precisely an IdentityUser<int>. Isn't this what it's looking for?

推荐答案

就遇到了这个问题。它崩溃的startup.cs文件。
改变

Ran into this problem. It was crashing on the startup.cs file. changed

services.AddIdentity<ApplicationUser, ApplicationIdentityRole>()
                .AddEntityFrameworkStores<ApplicationDbContext>()
                .AddDefaultTokenProviders();

到

services.AddIdentity<ApplicationUser, ApplicationIdentityRole>()
                .AddEntityFrameworkStores<ApplicationDbContext,int>()
                .AddDefaultTokenProviders();

宣布密钥类型似乎让过去的崩溃

declaring the key type seemed to get past the crash

这篇关于为什么会出现这种违反类型约束？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IT屋！