Use a custom command handler

By default the dispatcher resolves the registered ICommandHandler<> for the command type. You can bypass that and supply a delegate yourself when you need to — for example, to call a domain service directly, to compose existing handlers, or in test code.

Opt in per call

Pass a delegate as the second argument to Send or SendAndPublish:

var result = await dispatcher.Send(
    command,
    () => _somethingService.DoSomethingAsync(command));

var result = await dispatcher.SendAndPublish(
    command,
    () => _somethingService.DoSomethingAndPublishAsync(command));

The delegate’s return type must match what the registered handler would return — Task<Result> for ICommand, Task<Result<TResponse>> for ICommand<TResponse>.

Why you’d want to

• Compose existing services — when the work is already implemented somewhere else, you don’t need a thin pass-through handler.
• Inline test code — set up exactly the behaviour the test needs without registering a one-off handler.
• A/B experiments — pick between two implementations at dispatch time.

For everything else, the standard ICommandHandler<> discovered by AddMemoria is the right choice.

Related

• Quickstart: Mediator