IRequestHandler.Handle without parameter but returning T

Hello, I’m wondering how to model the situation bellow:

I have both Get:Create and Post:Create actions using the PRG pattern… Then I have a handler for the Get:Create that should return a viewModel/command with some filled data for the creation screen (could be a list of options it doesn’t matter).

I know that Mediatr provides IRequestHandler<T> for void Handle(T) and IRequestHandler<T,U> for U Handle(T). But the thing is that I don’t need to pass any parameters to this handler; i just want the return. How can I solve this?

[zachpainter77]

So I understand that MediatR, when sending a request, uses the Request Type and Reflection to look up the Request’s handler and executes.

My question is, what if your request object has no properties? What you end up with is an empty class that is only there so that MediatR knows which handler to execute.

Is this intended? Or is there a better way to deal with this that I am overlooking?

My question is: Is this the intended/accepted/supported way to handle this scenario with the MediatR library?

Thanks.

//Empty Request Class????
//Should I do this some other way?
public class GetAllThingsQuery : IRequest<List<Thing>> {}

public class GetAllThingsQueryHandler : IRequestHandler<GetAllThingsQuery, List<Thing>> 
{
    private readonly IRepository<Thing> _myRepo;

    public GetAllThingsQueryHandler(IRepository<Thing> myRepo)
    {
      _myRepo = myRepo;
    }

    public async Task<List<Thing>> Handle(GetAllThingsQuery request, CancellationToken cancellationToken)
    {
        return await _myRepo.GetAllAsync();
    {
}

//from controller or whatever
_mediator.Send(new GetAllThingsQuery());

I tried asking this question on stack overflow and they say that it is opinion based…

I have a similar scenario as above, where the only purpose of the request type is so that MediatR can find the handler for that particular query.

It looks like this is the way everybody does this with MediatR correct?

This isn’t an issue I’m only looking for confirmation on if what I am doing in my application is right or wrong and if there is another way or not?

Thanks.

[jbogard]

Empty message is the way to go. Even though the request may have zero values, the request type itself signals the intent of the request - and that itself is information!