MediatR
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.
Installing MediatR
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.
Using Contracts-Only Package
To reference only the contracts for MediatR, which includes:
IRequest
(including generic variants)INotification
IStreamRequest
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
IServiceCollection
Registering with 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:
IMediator
as transientISender
as transientIPublisher
as 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<,>));
});