c# - Multi-Context InMemory Database

Question

Is it possible to have an InMemory database (ASP.NET Core) that is shared across multiple DbContexts? It seems that each DbContext type keeps its own database, even when the same database name is specified in UseInMemoryDatabase.

Answer 1

This is possible nowadays, but indeed passing just the name is not enough if you use different context types. I'm using .net core 2.2 and had the exact same issue. My code now is now like this:

I create a InMemoryDatabaseRoot object like this in class level

//using Microsoft.EntityFrameworkCore.Storage;
private static readonly InMemoryDatabaseRoot InMemoryDatabaseRoot = new InMemoryDatabaseRoot();

When I add the db contextes I pass the root instance

services.AddDbContext<MyContext>(options =>
{
    options.UseInMemoryDatabase("MyContext", InMemoryDatabaseRoot);
    options.UseInternalServiceProvider(serviceProvider);
 });

 services.AddDbContext<MySecondContext>(options =>
 {
    options.UseInMemoryDatabase("MyContext", InMemoryDatabaseRoot);
    options.UseInternalServiceProvider(serviceProvider);
  });

I found it in a discussion here: https://github.com/aspnet/EntityFrameworkCore/issues/9613#issuecomment-430722420