ASP Net Core: add many to many relationship with IdentityUser

Question

i need to add a many to many relationship with UserIdentity in asp net core (i.e: a user can have many books and a book can have many user owners)

I have the book c

Answer 1

Simple, public string ApplicationUserId { get; set; }

ApplicationUser has a default key type of string.

If you do want to use int, simple do:

public class ApplicationUser : IdentityUser

Be sure to declare this relationship in your DbContext.

Here's a sample:

entityTypeBuilder.HasKey(pcp => new { pcp.CurrencyPairId, pcp.IsMain })
                .HasName("PartialCurrencyPair_CK_CurrencyPairId_IsMain");

            entityTypeBuilder.HasOne(pcp => pcp.Currency).WithMany(c => c.PartialCurrencyPairs)
                .HasForeignKey(pcp => pcp.CurrencyId)
                .HasConstraintName("PartialCurrencyPairs_Currency_Constraint");
            entityTypeBuilder.HasOne(pcp => pcp.CurrencyPair).WithMany(cp => cp.PartialCurrencyPairs)
                .HasForeignKey(pcp => pcp.CurrencyPairId)
                .HasConstraintName("PartialCurrencyPairs_CurrencyPair_Constraint");

EDIT

You don't have to explicitly define the generics together with the base class (IdentityUser). You simply do this:

services.AddIdentity()
                .AddEntityFrameworkStores()
                .AddDefaultTokenProviders();

This assumes Role and ApplicationUser share the same key type of string, where they are overloads of IdentityRole and IdentityUser respectively.