Remove boiler plate using(var db = new MyAppContext) from functions in entity framework

Question

It is a standard practice to wrap your data functions in using statement while using entity framework. e.g.

using(var db = new MyAppContext())
{
    return db.Books.ToList();
}

Often inside there is only one return statement. Is there a way to do this without having to write the using statement every time. With new c# feature the function will be much simpler to write.

public IList<Book> GetAllBooks() => db.Books.ToList()

There are lots and lots of methods I have that use this using block like that and if there is a way to do without it, it will make code much simpler.

Thank you in advance.

Answer 1

I can't say that I fully approve of what you're wanting, but, the following code:

public static class Extensions
{
    public static TOut DisposeWrapper<TDisposable, TOut>(this TDisposable input, Func<TDisposable,TOut> function) where TDisposable:IDisposable
    {
        try
        {
            return function(input);
        }
        finally
        {
            input.Dispose();
        }
    }
}

Alternately, you can wrap in using, which has the exact same effect and is perhaps a bit more terse:

public static class Extensions
{
    public static TOut DisposeWrapper<TDisposable, TOut>(this TDisposable input, Func<TDisposable,TOut> function) where TDisposable:IDisposable
    {
        using (input) return function(input);
    }
}

Will let you do something similar to what you're wanting. It's slightly verbose to use, example:

public static int ExampleUsage() => new Example().DisposeWrapper(x => x.SomeMethod());

And for completeness, here's the example class I used to test this functionality:

public class Example : IDisposable
{
    public void Dispose()
    {
        Console.WriteLine("I was disposed of");
    }

    public int SomeMethod() => 1;
}