asp.net - ASP.NET Identity DbContext 混淆

Question

IdentityModels.cs 中的这段代码带有默认 MVC 5 应用程序 - 这段代码适用于默认模板的所有 ASP.NET Identity 操作：

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
    public ApplicationDbContext()
        : base("DefaultConnection")
    {
    }
}

如果我使用带有实体框架的视图构建一个新控制器并在对话框中创建一个“新数据上下文...”，我会为我生成这个：

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Web;

namespace WebApplication1.Models
{
    public class AllTheOtherStuffDbContext : DbContext
    {
        // You can add custom code to this file. Changes will not be overwritten.
        // 
        // If you want Entity Framework to drop and regenerate your database
        // automatically whenever you change your model schema, please use data migrations.
        // For more information refer to the documentation:
        // http://msdn.microsoft.com/en-us/data/jj591621.aspx

        public AllTheOtherStuffDbContext() : base("name=AllTheOtherStuffDbContext")
        {
        }

        public System.Data.Entity.DbSet<WebApplication1.Models.Movie> Movies { get; set; }

    }
} 

如果我使用 EF 搭建另一个控制器 + 视图，例如对于 Animal 模型，这条新行将在下面自动生成public System.Data.Entity.DbSet<WebApplication1.Models.Movie> Movies { get; set; }- 如下所示：

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Web;

namespace WebApplication1.Models
{
    public class AllTheOtherStuffDbContext : DbContext
    {
        // You can add custom code to this file. Changes will not be overwritten.
        // 
        // If you want Entity Framework to drop and regenerate your database
        // automatically whenever you change your model schema, please use data migrations.
        // For more information refer to the documentation:
        // http://msdn.microsoft.com/en-us/data/jj591621.aspx

        public AllTheOtherStuffDbContext() : base("name=AllTheOtherStuffDbContext")
        {
        }

        public System.Data.Entity.DbSet<WebApplication1.Models.Movie> Movies { get; set; }
        public System.Data.Entity.DbSet<WebApplication1.Models.Animal> Animals { get; set; }

    }
} 

ApplicationDbContext（对于所有 ASP.NET 标识的东西）继承自IdentityDbContext，而后者又继承自DbContext. AllOtherStuffDbContext（对于我自己的东西）继承自DbContext.

所以我的问题是：

我应该将这两个 (ApplicationDbContext和AllOtherStuffDbContext) 中的哪一个用于我自己的所有其他模型？或者我应该只使用默认的自动生成ApplicationDbContext，因为使用它应该不是问题，因为它是从基类派生的DbContext，还是会有一些开销？你应该DbContext在你的应用程序中为你的所有模型只使用一个对象（我已经在某处读过这个）所以我什至不应该考虑在一个应用程序中同时使用这ApplicationDbContext两者AllOtherStuffDbContext？或者在 MVC 5 中使用 ASP.NET Identity 的最佳实践是什么？

Answer 1

我将使用从 IdentityDbContext 继承的单个 Context 类。这样，您可以让上下文了解您的类与 IdentityDbContext 的 IdentityUser 和 Roles 之间的任何关系。IdentityDbContext 的开销很小，它基本上是一个带有两个 DbSet 的常规 DbContext。一个用于用户，一个用于角色。

Answer 2

关于IdentityDbContext有很多困惑，在 Stackoverflow 中进行快速搜索，您会发现以下问题：
“ 为什么 Asp.Net Identity IdentityDbContext 是黑盒？
如何在使用 Visual Studio 2013 AspNet Identity 时更改表名？
将 MyDbContext 与 IdentityDbContext 合并"

要回答所有这些问题，我们需要了解IdentityDbContext只是从 DbContext 继承的一个类。
让我们看一下IdentityDbContext 源代码：

/// <summary>
/// Base class for the Entity Framework database context used for identity.
/// </summary>
/// <typeparam name="TUser">The type of user objects.</typeparam>
/// <typeparam name="TRole">The type of role objects.</typeparam>
/// <typeparam name="TKey">The type of the primary key for users and roles.</typeparam>
/// <typeparam name="TUserClaim">The type of the user claim object.</typeparam>
/// <typeparam name="TUserRole">The type of the user role object.</typeparam>
/// <typeparam name="TUserLogin">The type of the user login object.</typeparam>
/// <typeparam name="TRoleClaim">The type of the role claim object.</typeparam>
/// <typeparam name="TUserToken">The type of the user token object.</typeparam>
public abstract class IdentityDbContext<TUser, TRole, TKey, TUserClaim, TUserRole, TUserLogin, TRoleClaim, TUserToken> : DbContext
    where TUser : IdentityUser<TKey, TUserClaim, TUserRole, TUserLogin>
    where TRole : IdentityRole<TKey, TUserRole, TRoleClaim>
    where TKey : IEquatable<TKey>
    where TUserClaim : IdentityUserClaim<TKey>
    where TUserRole : IdentityUserRole<TKey>
    where TUserLogin : IdentityUserLogin<TKey>
    where TRoleClaim : IdentityRoleClaim<TKey>
    where TUserToken : IdentityUserToken<TKey>
{
    /// <summary>
    /// Initializes a new instance of <see cref="IdentityDbContext"/>.
    /// </summary>
    /// <param name="options">The options to be used by a <see cref="DbContext"/>.</param>
    public IdentityDbContext(DbContextOptions options) : base(options)
    { }

    /// <summary>
    /// Initializes a new instance of the <see cref="IdentityDbContext" /> class.
    /// </summary>
    protected IdentityDbContext()
    { }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of Users.
    /// </summary>
    public DbSet<TUser> Users { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of User claims.
    /// </summary>
    public DbSet<TUserClaim> UserClaims { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of User logins.
    /// </summary>
    public DbSet<TUserLogin> UserLogins { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of User roles.
    /// </summary>
    public DbSet<TUserRole> UserRoles { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of User tokens.
    /// </summary>
    public DbSet<TUserToken> UserTokens { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of roles.
    /// </summary>
    public DbSet<TRole> Roles { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of role claims.
    /// </summary>
    public DbSet<TRoleClaim> RoleClaims { get; set; }

    /// <summary>
    /// Configures the schema needed for the identity framework.
    /// </summary>
    /// <param name="builder">
    /// The builder being used to construct the model for this context.
    /// </param>
    protected override void OnModelCreating(ModelBuilder builder)
    {
        builder.Entity<TUser>(b =>
        {
            b.HasKey(u => u.Id);
            b.HasIndex(u => u.NormalizedUserName).HasName("UserNameIndex").IsUnique();
            b.HasIndex(u => u.NormalizedEmail).HasName("EmailIndex");
            b.ToTable("AspNetUsers");
            b.Property(u => u.ConcurrencyStamp).IsConcurrencyToken();

            b.Property(u => u.UserName).HasMaxLength(256);
            b.Property(u => u.NormalizedUserName).HasMaxLength(256);
            b.Property(u => u.Email).HasMaxLength(256);
            b.Property(u => u.NormalizedEmail).HasMaxLength(256);
            b.HasMany(u => u.Claims).WithOne().HasForeignKey(uc => uc.UserId).IsRequired();
            b.HasMany(u => u.Logins).WithOne().HasForeignKey(ul => ul.UserId).IsRequired();
            b.HasMany(u => u.Roles).WithOne().HasForeignKey(ur => ur.UserId).IsRequired();
        });

        builder.Entity<TRole>(b =>
        {
            b.HasKey(r => r.Id);
            b.HasIndex(r => r.NormalizedName).HasName("RoleNameIndex");
            b.ToTable("AspNetRoles");
            b.Property(r => r.ConcurrencyStamp).IsConcurrencyToken();

            b.Property(u => u.Name).HasMaxLength(256);
            b.Property(u => u.NormalizedName).HasMaxLength(256);

            b.HasMany(r => r.Users).WithOne().HasForeignKey(ur => ur.RoleId).IsRequired();
            b.HasMany(r => r.Claims).WithOne().HasForeignKey(rc => rc.RoleId).IsRequired();
        });

        builder.Entity<TUserClaim>(b => 
        {
            b.HasKey(uc => uc.Id);
            b.ToTable("AspNetUserClaims");
        });

        builder.Entity<TRoleClaim>(b => 
        {
            b.HasKey(rc => rc.Id);
            b.ToTable("AspNetRoleClaims");
        });

        builder.Entity<TUserRole>(b => 
        {
            b.HasKey(r => new { r.UserId, r.RoleId });
            b.ToTable("AspNetUserRoles");
        });

        builder.Entity<TUserLogin>(b =>
        {
            b.HasKey(l => new { l.LoginProvider, l.ProviderKey });
            b.ToTable("AspNetUserLogins");
        });

        builder.Entity<TUserToken>(b => 
        {
            b.HasKey(l => new { l.UserId, l.LoginProvider, l.Name });
            b.ToTable("AspNetUserTokens");
        });
    }
}

根据源代码，如果我们想将 IdentityDbContext 与 DbContext 合并，我们有两个选项：

第一个选项：
创建一个继承自 IdentityDbContext 并有权访问类的 DbContext。

   public class ApplicationDbContext 
    : IdentityDbContext
{
    public ApplicationDbContext()
        : base("DefaultConnection")
    {
    }

    static ApplicationDbContext()
    {
        Database.SetInitializer<ApplicationDbContext>(new ApplicationDbInitializer());
    }

    public static ApplicationDbContext Create()
    {
        return new ApplicationDbContext();
    }

    // Add additional items here as needed
}

额外说明：

1）我们还可以通过以下解决方案更改asp.net Identity默认表名：

    public class ApplicationDbContext : IdentityDbContext
    {    
        public ApplicationDbContext(): base("DefaultConnection")
        {
        }

        protected override void OnModelCreating(System.Data.Entity.DbModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            modelBuilder.Entity<IdentityUser>().ToTable("user");
            modelBuilder.Entity<ApplicationUser>().ToTable("user");

            modelBuilder.Entity<IdentityRole>().ToTable("role");
            modelBuilder.Entity<IdentityUserRole>().ToTable("userrole");
            modelBuilder.Entity<IdentityUserClaim>().ToTable("userclaim");
            modelBuilder.Entity<IdentityUserLogin>().ToTable("userlogin");
        }
    }

2) 此外，我们可以扩展每个类并将任何属性添加到类，如“IdentityUser”、“IdentityRole”……

    public class ApplicationRole : IdentityRole<string, ApplicationUserRole>
{
    public ApplicationRole() 
    {
        this.Id = Guid.NewGuid().ToString();
    }

    public ApplicationRole(string name)
        : this()
    {
        this.Name = name;
    }

    // Add any custom Role properties/code here
}


// Must be expressed in terms of our custom types:
public class ApplicationDbContext 
    : IdentityDbContext<ApplicationUser, ApplicationRole, 
    string, ApplicationUserLogin, ApplicationUserRole, ApplicationUserClaim>
{
    public ApplicationDbContext()
        : base("DefaultConnection")
    {
    }

    static ApplicationDbContext()
    {
        Database.SetInitializer<ApplicationDbContext>(new ApplicationDbInitializer());
    }

    public static ApplicationDbContext Create()
    {
        return new ApplicationDbContext();
    }

    // Add additional items here as needed
}

为了节省时间，我们可以使用AspNet Identity 2.0 可扩展项目模板来扩展所有类。

第二种选择：（不推荐）
如果我们自己编写所有代码，实际上不必从 IdentityDbContext 继承。
所以基本上我们可以从 DbContext 继承并从IdentityDbContext 源代码中实现我们定制的“OnModelCreating(ModelBuilder builder)”版本

Answer 3

对于人们来说，这是一个较晚的条目，但下面是我的实现。您还会注意到我取消了更改 KEYs 默认类型的能力：有关其的详细信息可以在以下文章中找到：

• 扩展身份模型并使用整数键而不是字符串
• 在 ASP.NET 标识中更改用户的主键

注意：
应该注意，您不能使用Guid's您的钥匙。这是因为在引擎盖下它们是 a Struct，因此没有拆箱，这将允许它们从通用<TKey>参数转换。

类看起来像：

public class ApplicationDbContext : IdentityDbContext<ApplicationUser, CustomRole, string, CustomUserLogin, CustomUserRole, CustomUserClaim>
{
    #region <Constructors>

    public ApplicationDbContext() : base(Settings.ConnectionString.Database.AdministrativeAccess)
    {
    }

    #endregion

    #region <Properties>

    //public DbSet<Case> Case { get; set; }

    #endregion

    #region <Methods>

    #region

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        //modelBuilder.Configurations.Add(new ResourceConfiguration());
        //modelBuilder.Configurations.Add(new OperationsToRolesConfiguration());
    }

    #endregion

    #region

    public static ApplicationDbContext Create()
    {
        return new ApplicationDbContext();
    }

    #endregion

    #endregion
}

    public class ApplicationUser : IdentityUser<string, CustomUserLogin, CustomUserRole, CustomUserClaim>
    {
        #region <Constructors>

        public ApplicationUser()
        {
            Init();
        }

        #endregion

        #region <Properties>

        [Required]
        [StringLength(250)]
        public string FirstName { get; set; }

        [Required]
        [StringLength(250)]
        public string LastName { get; set; }

        #endregion

        #region <Methods>

        #region private

        private void Init()
        {
            Id = Guid.Empty.ToString();
        }

        #endregion

        #region public

        public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<ApplicationUser, string> manager)
        {
            // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
            var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);

            // Add custom user claims here

            return userIdentity;
        }

        #endregion

        #endregion
    }

    public class CustomUserStore : UserStore<ApplicationUser, CustomRole, string, CustomUserLogin, CustomUserRole, CustomUserClaim>
    {
        #region <Constructors>

        public CustomUserStore(ApplicationDbContext context) : base(context)
        {
        }

        #endregion
    }

    public class CustomUserRole : IdentityUserRole<string>
    {
    }

    public class CustomUserLogin : IdentityUserLogin<string>
    {
    }

    public class CustomUserClaim : IdentityUserClaim<string> 
    { 
    }

    public class CustomRoleStore : RoleStore<CustomRole, string, CustomUserRole>
    {
        #region <Constructors>

        public CustomRoleStore(ApplicationDbContext context) : base(context)
        {
        } 

        #endregion
    }

    public class CustomRole : IdentityRole<string, CustomUserRole>
    {
        #region <Constructors>

        public CustomRole() { }
        public CustomRole(string name) 
        { 
            Name = name; 
        }

        #endregion
    }

Answer 4

如果您深入研究 IdentityDbContext 的抽象，您会发现它看起来就像您的派生 DbContext。最简单的方法是 Olav 的回答，但如果您想更好地控制所创建的内容并减少对 Identity 包的依赖，请查看我的问题和回答here。如果您点击链接，则有一个代码示例，但总而言之，您只需将所需的 DbSet 添加到您自己的 DbContext 子类中。