.net-core Dependency Injection

Question

I have a Generic repository which I want to register for DI, it implements an interface IRepository.

Normally I would create an instance of it like this:

IRepository repo = new Repository<Order>();

However I am trying to get up to speed in .net 5 ahead of release and want to get this working with DI, I have resorted to the following :

services.AddTransient<DAL.IRepository<Models.Order>, DAL.Repository<Models.Order>>();

But this feels wrong, I don't want 50+ lines in there one for each of the classes in my model...

I cannot find anything online about this, I know its possible with other ioc containers.. but as this is a learning project I dont want to use another container, Im aiming to do it all with .net5s native container.

Answer 1

After some back and forwards in the comments to other answers I have a working solution, It might not be the best way but it works. Ill update again if I find a better way to implement this.

The two issues I had were : Needed to register a generic interface, the issue here was a lapse in concentration on my part.. I had the syntax wrong for registering a generic type which of course is :

services.AddTransient(typeof(IRepository<>), typeof(Repository<>));

The second issue was that I have an assembly which contains 50+ different models which I wanted registered, The way that I addressed this was to write a method that I can pass a list of assemblies to along with the Namespace that I want to register and it iterates over any types that match the criteria and registers them in the DI container.

public void RegisterModels(IServiceCollection services, string[] Assemblies, string @NameSpace)
    {
        foreach (var a in Assemblies)
        {
            Assembly loadedAss = Assembly.Load(a);

            var q = from t in loadedAss.GetTypes()
                    where t.IsClass && !t.Name.Contains("<") && t.Namespace.EndsWith(@NameSpace)
                    select t;

            foreach (var t in q.ToList())
            {
                Type.GetType(t.Name);
                services.AddTransient(Type.GetType(t.FullName), Type.GetType(t.FullName));
            }
        }
    }

This is then called from the startup.cs method ConfigureServices :

public void ConfigureServices(IServiceCollection services)
    {
        // Add framework services.
        services.AddEntityFramework()
            .AddSqlServer()
            .AddDbContext<TestContext>(options =>
                options.UseSqlServer(@"Server=LOCALHOST\SQLEXPRESS;Database=Test;Trusted_Connection=True;"));

        services.AddMvc();

        RegisterModels(services, new string[] { "UI" }, "UI.Models");

        services.AddTransient(typeof(IRepository<>), typeof(Repository<>));
    }

There may be a better way to do this, there definitely is using different DI containers, if anyone has improvements to offer please let me know.