Ninject - In what scope DbContext should get binded when RequestScope is meaningless?

问题

In an MVC / WebAPI environment I would use InRequestScope to bind the DbContext.

However, I am now on a Console application / Windows service / Azure worker role (doesn't really matter, just there's no Web request scope), which periodically creates a number of Tasks that run asynchronously. I would like each task to have its own DbContext, and since tasks run on their own thread, I tried binding DbContext using InThreadScope.

Unfortunately, I realize that the DbContext is not disposed when a task is finished. What actually happens is, the thread returns to the Thread Pool and when it is assigned a new task, it already has a DbContext, so DbContexts stay alive forever.

Is there a way InThreadScope can be used here or should I use some other scope? How can ThreadScope be used when threads are returning from ThreadPool every now and then?

回答1:

If you decide to go on with custom scope, the solution is:

public sealed class CurrentScope : INotifyWhenDisposed
{
    [ThreadStatic]
    private static CurrentScope currentScope;

    private CurrentScope()
    {
    }

    public static CurrentScope Instance => currentScope ?? (currentScope = new CurrentScope());

    public bool IsDisposed { get; private set; }

    public event EventHandler Disposed;

    public void Dispose()
    {
        this.IsDisposed = true;
        currentScope = null;
        if (this.Disposed != null)
        {
            this.Disposed(this, EventArgs.Empty);
        }
    }
}

Binding:

Bind<DbContext>().To<MyDbContext>().InScope(c => CurrentScope.Instance)

And finally:

using (CurrentScope.Instance)
{
    // your request...
    // you'll get always the same DbContext inside of this using block
    // DbContext will be disposed after going out of scope of this using block
}

来源：https://stackoverflow.com/questions/23081707/ninject-in-what-scope-dbcontext-should-get-binded-when-requestscope-is-meaning