Dependency injection, inject with parameters

Question

I'm using vNext implementation of DI. How to pass parameters to constructor? For example, i have class:

public class RedisCacheProvider : ICacheProvider {     private readonly string _connectionString;      public RedisCacheProvider(string connectionString)     {         _connectionString = connectionString;     }     //interface methods implementation... } 

And service register:

services.AddSingleton<ICacheProvider, RedisCacheProvider>(); 

How to pass parameter to constructor of RedisCacheProvider class? For example for Autofac:

builder.RegisterType<RedisCacheProvider>()        .As<ICacheProvider>()        .WithParameter("connectionString", "myPrettyLocalhost:6379"); 

Answer 1

You can either provide a delegate to manually instantiate your cache provider or directly provide an instance:

services.AddSingleton<ICacheProvider>(provider => new RedisCacheProvider("myPrettyLocalhost:6379"));  services.AddSingleton<ICacheProvider>(new RedisCacheProvider("myPrettyLocalhost:6379")); 

Please note that the container will not explicitly dispose of manually instantiated types, even if they implement IDisposable. See the ASP.NET Core doc about Disposal of Services for more info.

Answer 2

If the constructur also has dependencies that should be resolved by DI you can use that:

public class RedisCacheProvider : ICacheProvider {     private readonly string _connectionString;     private readonly IMyInterface _myImplementation;      public RedisCacheProvider(string connectionString, IMyInterface myImplementation)     {         _connectionString = connectionString;         _myImplementation = myImplementation;     }     //interface methods implementation... }  

Startup.cs:

services.AddSingleton<IMyInterface, MyInterface>(); services.AddSingleton<ICacheProvider>(provider =>      RedisCacheProvider("myPrettyLocalhost:6379", provider.GetService<IMyInterface>()));