Add custom column in AspNetRoles results in Invalid Column Name Discriminator

Question

I'm using ASP.NET MVC5 with Identity 2 framework, Database first

I'm trying to custom AspNetRoles, by adding a column called MyCustomColumn

However, my app crashes because :

Invalid Column Name Discriminator

There is a lot of resources on SO and elsewhere on the web, but most of them are with CodeFirst approach and I can't use them in my app.

How to deal with it ?

Answer 1

Ok, as I spend some hours to find a solution, I post it here, if it could help someone else.

First, in AspNetRoles, create your custom column AND a column called Discriminator (which is a nvarchar(max) ). Update your .edmx

Then, we have to create a class which inherits from IdentityRole. We will use this class to access our custom column we just created :

In Models folder

public ApplicationRole()
        : base() { }

    public ApplicationRole(string name, long myCustomValue)
        : base(name)
    {
        MyCustomValue = myCustomValue;
    }

    public virtual long MyCustomValue { get; set; }

Then, let's create a class which inherits from RoleManager<ApplicationRole>. I placed it in IdentityConfig.cs, but maybe it's a best practice to place it elsewhere...
For information, I get inspired by this blog, Re-Implementing RoleStore and ApplicationRoleManager paragraph

public class ApplicationRoleManager : RoleManager<ApplicationRole>
{
    public ApplicationRoleManager(
        IRoleStore<ApplicationRole, string> roleStore)
        : base(roleStore)
    {
    }
    public static ApplicationRoleManager Create(
        IdentityFactoryOptions<ApplicationRoleManager> options, IOwinContext context)
    {
        return new ApplicationRoleManager(
            new RoleStore<ApplicationRole>(context.Get<ApplicationDbContext>()));
    }
}

ApplicationRoleManager has a constructor which calls our previously created ApplicationRole class.

Now we have to register our ApplicationRoleManager at startup, so we have to add this line after the others CreatePerOwinContext

In App_Start\Startup.auth.cs, ConfigureAuth(IAppBuilder app) method

app.CreatePerOwinContext<ApplicationRoleManager>(ApplicationRoleManager.Create);

So now we can use our ApplicationRoleManager, correctly instanciated :

var rm = new ApplicationRoleManager(new RoleStore<ApplicationRole>(new ApplicationDbContext()));

And then use it as we want

var roleName = rm.FindByName("Admin");
string myCustomData = roleName.CustomData.ToString();