Use DbContext in ASP .Net Singleton Injected Class

Question

I need to access my database in a Singleton class instantiated in my Startup class. It seems that injecting it directly results in a DbContext that is disposed.

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Answer 1

Original source: https://entityframeworkcore.com/knowledge-base/51939451/how-to-use-a-database-context-in-a-singleton-service-

Since DbContext is scoped by default, you need to create scope to access it. It also allows you to handle its lifetime correctly - otherwise you'd keep instance of DbContext for a long time and this is not recommended.

public class Singleton : ISingleton 
{

    private readonly IServiceScopeFactory scopeFactory;

    public Singleton(IServiceScopeFactory scopeFactory)
    {
        this.scopeFactory = scopeFactory;
    }

    public void MyMethod() 
    {
        using(var scope = scopeFactory.CreateScope()) 
        {
            var db = scope.ServiceProvider.GetRequiredService();

            // when we exit the using block,
            // the IServiceScope will dispose itself 
            // and dispose all of the services that it resolved.
        }
    }
}