dotnet
EFCore - DI - How to initialize service only once per unique DBContext
Dependency Injection allows services to be added in DI container in 3 ways (based on the service lifetime) Singleton, Scoped or Transient.
For a EFCore provider if someone wants a service to be created only once per unique db context, what would be the correct way to add the service to the container.
For Ex:- suppose a sample application is using 2 instances of same dbcontext
using (var context1 = new ModelContext())
{
...
...
}
using (var context2 = new ModelContext())
{
...
...
}
But there is a service 'X' which the EFCore provider implements and only want it to be initialized once per unique dbcontext. What would be the correct way to add the service to DI container.
Adding the service as Singleton would initialize the service only once during the lifetime of the application. So multiple instances of different dbcontext ( say ModelContext1 and ModelContext2) would also use the same service instance, which is not desirable.
Adding the service as Scoped would initialize the service for each instance of dbcontext (whether same or different). However I want to use the same service instance if dbcontext is same and different service instance if dbcontext is different. Is there some way to achieve this? Please could someone let me know.
Include provider and version information
EF Core version: 7.0.0 Database provider: Microsoft.EntityFrameworkCore.SqlServer Target framework: .NET 6.0 Operating system: Windows 10 IDE: Visual Studio 2022 17.4
@shvmgpt116 As far as I know, this is not possible. You could instead create a singleton factory and have it create an instance per context type as needed.
@shvmgpt116 simply register a custom registry type that has a Dictionary<Type, T> as a singleton in your context, and have that injected wherever you need it. Then, simply look up the T given your context type.
Note it should be a ConcurrentDictionary, or something else that will be thread safe, since the singleton service will be shared.