迁移.NET Framework MVC到ASP.NET Core 6.0遇Identity用户声明错误

System.InvalidOperationException: 'The relationship from 'IdentityUserClaim' to 'User' with foreign key properties {'UserId' : string} cannot target the primary key {'Id' : int} because it is not compatible. Configure a principal key or a set of foreign key properties with compatible types for this relationship.'

错误原因 #

自定义User实体继承了默认主键为string的IdentityUser，但手动声明了int类型的Id属性，导致User主键类型变为int；而AspNetUserClaim等关联实体的UserId仍配置为string类型，两者类型不匹配，引发外键关联错误。

相关代码 #

DbContext #

public class DbContext : IdentityDbContext<User>
{
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<AspNetRole>(entity =>
            {
                entity.HasIndex(e => e.Name, "RoleNameIndex")
                    .IsUnique()
                    .HasFillFactor(80);

                entity.Property(e => e.Id).HasMaxLength(128);

                entity.Property(e => e.Name)
                    .IsRequired()
                    .HasMaxLength(256);
            });

            modelBuilder.Entity<AspNetUser>(entity =>
            {
                entity.HasIndex(e => e.UserName, "UserNameIndex")
                    .IsUnique()
                    .HasFillFactor(80);

                entity.Property(e => e.Id).HasMaxLength(128);

                entity.Property(e => e.Email).HasMaxLength(256);

                entity.Property(e => e.LockoutEndDateUtc).HasColumnType("datetime");

                entity.Property(e => e.UserName)
                    .IsRequired()
                    .HasMaxLength(256);

                entity.HasMany(d => d.Roles)
                    .WithMany(p => p.Users)
                    .UsingEntity<Dictionary<string, object>>(
                        "AspNetUserRole",
                        l => l.HasOne<AspNetRole>().WithMany().HasForeignKey("RoleId").HasConstraintName("FK_dbo.AspNetUserRoles_dbo.AspNetRoles_RoleId"),
                        r => r.HasOne<AspNetUser>().WithMany().HasForeignKey("UserId").HasConstraintName("FK_dbo.AspNetUserRoles_dbo.AspNetUsers_UserId"),
                        j =>
                        {
                            j.HasKey("UserId", "RoleId").HasName("PK_dbo.AspNetUserRoles");

                            j.ToTable("AspNetUserRoles");

                            j.HasIndex(new[] { "RoleId" }, "IX_RoleId").HasFillFactor(80);

                            j.HasIndex(new[] { "UserId" }, "IX_UserId").HasFillFactor(80);

                            j.IndexerProperty<string>("UserId").HasMaxLength(128);

                            j.IndexerProperty<string>("RoleId").HasMaxLength(128);
                        });
            });

            modelBuilder.Entity<AspNetUserClaim>(entity =>
            {
                entity.HasIndex(e => e.UserId, "IX_UserId")
                    .HasFillFactor(80);

                entity.Property(e => e.UserId)
                    .IsRequired()
                    .HasMaxLength(128);

                entity.HasOne(d => d.User)
                    .WithMany(p => p.AspNetUserClaims)
                    .HasForeignKey(d => d.UserId)
                    .HasConstraintName("FK_dbo.AspNetUserClaims_dbo.AspNetUsers_UserId");
            });

            modelBuilder.Entity<AspNetUserLogin>(entity =>
            {
                entity.HasKey(e => new { e.LoginProvider, e.ProviderKey, e.UserId })
                    .HasName("PK_dbo.AspNetUserLogins");

                entity.HasIndex(e => e.UserId, "IX_UserId")
                    .HasFillFactor(80);

                entity.Property(e => e.LoginProvider).HasMaxLength(128);

                entity.Property(e => e.ProviderKey).HasMaxLength(128);

                entity.Property(e => e.UserId).HasMaxLength(128);

                entity.HasOne(d => d.User)
                    .WithMany(p => p.AspNetUserLogins)
                    .HasForeignKey(d => d.UserId)
                    .HasConstraintName("FK_dbo.AspNetUserLogins_dbo.AspNetUsers_UserId");
            });

            modelBuilder.Entity<User>(entity =>
            {
                entity.ToTable("User");
            });
        }
}

User实体 #

public class User : IdentityUser
{
    public int Id { get; set; }
    public string Username { get; set; }
}

已尝试的修改 #

User实体修改 #

public virtual ICollection<AspNetUserClaim> AspNetUserClaims { get; set; } = new HashSet<AspNetUserClaim>();

DbContext的OnModelCreating修改 #

entity.HasMany(x => x.AspNetUserClaims)
    .WithOne()
    .HasForeignKey(x => x.UserId)
    .IsRequired()
    .OnDelete(DeleteBehavior.Cascade);

解决方案 #

1. 修正User实体的继承关系 #

继承IdentityUser<int>指定主键类型为int，无需手动声明Id属性（基类已包含）：

public class User : IdentityUser<int>
{
    public string Username { get; set; }
    public virtual ICollection<AspNetUserClaim> AspNetUserClaims { get; set; } = new HashSet<AspNetUserClaim>();
}

2. 修正DbContext的继承与配置 #

使用IdentityDbContext<User, IdentityRole<int>, int>匹配主键类型，并更新所有关联实体的主键/外键类型配置：

public class YourDbContext : IdentityDbContext<User, IdentityRole<int>, int>
{
    // 构造函数（根据依赖注入方式调整）
    public YourDbContext(DbContextOptions<YourDbContext> options) : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        // 先调用基类方法确保Identity默认配置生效
        base.OnModelCreating(modelBuilder);

        modelBuilder.Entity<AspNetRole>(entity =>
        {
            entity.HasIndex(e => e.Name, "RoleNameIndex")
                .IsUnique()
                .HasFillFactor(80);

            // 移除string类型的Id长度配置，改为int类型主键
            // entity.Property(e => e.Id).HasMaxLength(128);

            entity.Property(e => e.Name)
                .IsRequired()
                .HasMaxLength(256);
        });

        modelBuilder.Entity<AspNetUser>(entity =>
        {
            entity.HasIndex(e => e.UserName, "UserNameIndex")
                .IsUnique()
                .HasFillFactor(80);

            // 移除string类型的Id长度配置
            // entity.Property(e => e.Id).HasMaxLength(128);

            entity.Property(e => e.Email).HasMaxLength(256);
            entity.Property(e => e.LockoutEndDateUtc).HasColumnType("datetime");
            entity.Property(e => e.UserName)
                .IsRequired()
                .HasMaxLength(256);

            entity.HasMany(d => d.Roles)
                .WithMany(p => p.Users)
                .UsingEntity<Dictionary<string, object>>(
                    "AspNetUserRole",
                    l => l.HasOne<AspNetRole>().WithMany().HasForeignKey("RoleId").HasConstraintName("FK_dbo.AspNetUserRoles_dbo.AspNetRoles_RoleId"),
                    r => r.HasOne<AspNetUser>().WithMany().HasForeignKey("UserId").HasConstraintName("FK_dbo.AspNetUserRoles_dbo.AspNetUsers_UserId"),
                    j =>
                    {
                        j.HasKey("UserId", "RoleId").HasName("PK_dbo.AspNetUserRoles");
                        j.ToTable("AspNetUserRoles");
                        j.HasIndex(new[] { "RoleId" }, "IX_RoleId").HasFillFactor(80);
                        j.HasIndex(new[] { "UserId" }, "IX_UserId").HasFillFactor(80);

                        // 改为int类型的外键配置
                        j.IndexerProperty<int>("UserId");
                        j.IndexerProperty<int>("RoleId");
                    });
        });

        modelBuilder.Entity<AspNetUserClaim>(entity =>
        {
            entity.HasIndex(e => e.UserId, "IX_UserId")
                .HasFillFactor(80);

            // 移除string类型的UserId长度配置，改为int类型
            entity.Property(e => e.UserId)
                .IsRequired();

            entity.HasOne(d => d.User)
                .WithMany(p => p.AspNetUserClaims)
                .HasForeignKey(d => d.UserId)
                .HasConstraintName("FK_dbo.AspNetUserClaims_dbo.AspNetUsers_UserId");
        });

        modelBuilder.Entity<AspNetUserLogin>(entity =>
        {
            entity.HasKey(e => new { e.LoginProvider, e.ProviderKey, e.UserId })
                .HasName("PK_dbo.AspNetUserLogins");

            entity.HasIndex(e => e.UserId, "IX_UserId")
                .HasFillFactor(80);

            entity.Property(e => e.LoginProvider).HasMaxLength(128);
            entity.Property(e => e.ProviderKey).HasMaxLength(128);

            // 改为int类型的UserId
            entity.Property(e => e.UserId)
                .IsRequired();

            entity.HasOne(d => d.User)
                .WithMany(p => p.AspNetUserLogins)
                .HasForeignKey(d => d.UserId)
                .HasConstraintName("FK_dbo.AspNetUserLogins_dbo.AspNetUsers_UserId");
        });

        modelBuilder.Entity<User>(entity =>
        {
            entity.ToTable("User");
        });
    }
}

3. 修正AspNetUserClaim等关联实体的UserId类型 #

确保AspNetUserClaim的UserId为int类型：

public class AspNetUserClaim
{
    // 其他属性保持不变
    public int UserId { get; set; }
    public User User { get; set; }
}

通过以上修改，统一所有Identity相关实体的主键与外键类型为int，即可解决类型不兼容的关联错误。

内容的提问来源于stack exchange，提问作者Bad Dub