Using Dapper.CX with Dependency Injection

Most of the work setting up Dapper.CX for use with dependency injection involves creating components that allow ASP.NET Identity to integrate with your user profile model class in a scalable way. Just about any application you create will require authentication, and you'll have a model class in your application that represents users. What you want to avoid, however, is querying the user profile model from your database with every page view. A more scalable solution is to query user properties once during login, and to capture the profile data as a set of Claims. In turn, Dapper.CX converts these Claims into your user profile model so you have strong-typed access to user profile data at all times. The procedure outlined below describes how to enable your user profile model properties to get this working:

1. Add a model class to your project that implements IUserBase. Example: UserProfile.

2. Add NuGet package Dapper.CX.SqlServer.AspNetCore to your project.

3. Add a service to your project that derives from abstract class DbUserClaimsConverter<TUser>. This used to convert your user profile model class to a set of claims that map onto it. Example: UserProfileClaimsConverter

4. Add a service to your project that derives from DbUserClaimsFactory<TUser>. Example: UserProfileClaimsFactory. This is used when adding identity during your application startup. This uses the DbUserclaimsFactory<TUser> class you created in step 3, and allows Identity to generate your desired claims when users log in. See example:

services
    .AddDefaultIdentity<IdentityUser>(options => options.SignIn.RequireConfirmedAccount = true)
    .AddEntityFrameworkStores<ApplicationDbContext>()
    .AddClaimsPrincipalFactory<UserProfileClaimsFactory>();

5. Use the AddDapperCX extension method in your application startup, like this example:

services.AddDapperCX(
    connectionString, 
    (id) => Convert.ToInt32(id), 
    () => new UserProfileClaimsConverter(connectionString));

The AddDapperCX extension method accepts a database connection string, a delegate that returns your identity column type of choice (-- currently int and long are supported), and lastly a factory that instantiates your DbUserClaimsConverter<TUser> that you created in step 3 above.

Now, you can inject the Dapper.CX SqlServerCrudService<TIdentity, TUser> into your pages or components as per this example.

public class BasePageModel : PageModel
{
    public BasePageModel(DapperCX<int, UserProfile> data)
    {
        Data = data;
    }

    public DapperCX<int, UserProfile> Data { get; }
}

Here, I use a read-only property Data as the accessor for all CRUD operations. The DapperCX class derives from SqlCrudService. Learn more here.