I'm just starting with Asp.net core Dependency Injection, and my concept could be inaccurate. This docs.asp.net post explains how to inject context to a controller. I have little confusion regarding injection, in testing perspective. Assume we have following scenario:
public interface ITasksRepository
{
public void Create();
}
//This is fake implementation, using fake DbContext for testing purpose
public class TasksRepositoryFake : ITasksRepository
{
public void Create()
{
FakeDbContext.Add(sometask);
//logic;
}
}
//This is actual implementation, using actual DbContext
public class TasksRepository : ITasksRepository
{
public void Create()
{
DbContext.Add(someTask);
//logic;
}
}
Now in order to inject context in controller, we design it as:
public class TasksController : Controller
{
public ITasksRepository TaskItems { get; set; }
public TodoController(ITaskRepository taskItems)
{
TaskItems = taskItems;
}
//other logic
}
What asp.net core provides as builtin feature is, we can register the dependency injection in startup class as follows:
public void ConfigureServices(IServiceCollection services)
{
// Add framework services.
services.AddMvc();
services.AddSingleton<ITasksRepository, TasksRepositoryFake>();
}
According to this logic, my TaskRepositoryFake will be injected to the controller. So far, everything is clear. My questions/confusions regarding this are as follows:
Questions:
- How can I use this builtin DI feature to inject the context using some logic? May be programatically, or configuration based, or environment based? (for example, always inject fake context, when using 'test' environment? etc.)
- Is it even possible? If we always have to change this manually in StartUp class, then how does this builtin DI feature serve us? Because we could have simply done that in controller, without this feature.
