Simple mediator implementation in .NET
In-process messaging with no dependencies.
Supports request/response, commands, queries, notifications and events, synchronous and async with intelligent dispatching via C# generic variance.
Examples in the wiki.
You should install MediatR with NuGet:
Install-Package MediatR
Or via the .NET Core command line interface:
dotnet add package MediatR
Either commands, from Package Manager Console or .NET Core CLI, will download and install MediatR and all required dependencies.
To reference only the contracts for MediatR, which includes:
IRequest(including generic variants)INotificationIStreamRequest
Add a package reference to MediatR.Contracts
This package is useful in scenarios where your MediatR contracts are in a separate assembly/project from handlers. Example scenarios include:
- API contracts
- GRPC contracts
- Blazor
MediatR supports Microsoft.Extensions.DependencyInjection.Abstractions directly. To register various MediatR services and handlers:
services.AddMediatR(cfg => cfg.RegisterServicesFromAssemblyContaining<Startup>());
or with an assembly:
services.AddMediatR(cfg => cfg.RegisterServicesFromAssembly(typeof(Startup).Assembly));
This registers:
IMediatoras transientISenderas transientIPublisheras transientIRequestHandler<,>concrete implementations as transientIRequestHandler<>concrete implementations as transientINotificationHandler<>concrete implementations as transientIStreamRequestHandler<>concrete implementations as transientIRequestPreProcessor<>concrete implementations as transientIRequestPostProcessor<,>concrete implementations as transientIRequestExceptionHandler<,,>concrete implementations as transientIRequestExceptionAction<,>)concrete implementations as transient
This also registers open generic implementations for:
INotificationHandler<>IRequestPreProcessor<>IRequestPostProcessor<,>IRequestExceptionHandler<,,>IRequestExceptionAction<,>
To register behaviors:
services.AddMediatR(cfg => {
cfg.RegisterServicesFromAssembly(typeof(Startup).Assembly);
cfg.AddBehavior<IPipelineBehavior<Ping, Pong>, PingPongBehavior>();
cfg.AddOpenBehavior(typeof(GenericBehavior<,>));
});