实体框架核心与IdentityUser的多对多关系

Question

I am looking a way to bind the default IdentityUser with a custom class but I am getting this error:

Column names in each table must be unique. Column name 'AppUserId' in table 'HMTUser' is specified more than once.

AppUser class:

public class AppUser : IdentityUser
{
    public string FName { get; set; }
    public string LName { get; set; }

    public List<HMTUser> HMTUsers { get; set; }
}

HMT class:

public class HMT
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int HID { get; set; }
    public string Name { get; set; }

    public List<HMTUser> HMTUsers { get; set; }
}

HUser class:

public class HMTUser
{
    public int AppUserID { get; set; }
    public AppUser AppUser { get; set; }

    public int HHID { get; set; }
    public HMT HMT { get; set; }
}

and have defined the OnModelCreating with

modelBuilder.Entity<HMTUser>()
            .HasKey(s=> new { s.HHID , s.AppUserID });

I am uncertain on int part as AppUser is derived from IdentityUser and id is varchar , will this be the case?

UPDATE

Changing the int to string did the job but ef core was asking for a PK in HMTUser entity so made a new one using

[Key]

It works but it also create a new table name

'AppUser'

which is not used to store user data, user data is still saved in default

'AspNetUsers'

table.

Answer 1

I have tested your code and I think one solution is to change the type of the AppUserId from int to string . With this change everything works fine. The code generated after migration:

migrationBuilder.CreateTable(
            name: "HMTUsers",
            columns: table => new
            {
                AppUserId = table.Column<string>(nullable: false),
                HHID = table.Column<int>(nullable: false),
                HMTHID = table.Column<int>(nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_HMTUsers", x => new { x.HHID, x.AppUserId });
                table.ForeignKey(
                    name: "FK_HMTUsers_AppUsers_AppUserId",
                    column: x => x.AppUserId,
                    principalTable: "AppUsers",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
                table.ForeignKey(
                    name: "FK_HMTUsers_HTMs_HMTHID",
                    column: x => x.HMTHID,
                    principalTable: "HTMs",
                    principalColumn: "HID",
                    onDelete: ReferentialAction.Restrict);
            });