Is there a way to return Anonymous Type from method?

user_136258 0
Viewed 65497

I know I can't write a method like:

public var MyMethod()
{
   return new{ Property1 = "test", Property2="test"};
}

I can do it otherwise:

public object MyMethod()
{
   return new{ Property1 = "test", Property2="test"}
}

but I don't want to do the second option because, if I do so, I will have to use reflection.

Why I want to do that:

Today i have a method inside my aspx page that returns a datatable as result and I cannot change it, I was trying to convert this DataTable to an Anonymous method with the properties that I want to work with. I didn't want to create a class only to do that and as I will need to perform the same query more than one time, I Thought to create a method that returns an anonymous type would be a good ideia.

anonymous-types .net c#
11 Answers

As alternative, starting C# 7 we can use ValueTuple. A little example from here:

public (int sum, int count) DoStuff(IEnumerable<int> values) 
{
    var res = (sum: 0, count: 0);
    foreach (var value in values) { res.sum += value; res.count++; }
    return res;
}

And on the receiving end:

var result = DoStuff(Enumerable.Range(0, 10));
Console.WriteLine($"Sum: {result.Sum}, Count: {result.Count}");

Or:

var (sum, count) = DoStuff(Enumerable.Range(0, 10));
Console.WriteLine($"Sum: {sum}, Count: {count}");
user_9854570

You could also invert your control flow if possible:

    public abstract class SafeAnon<TContext>
    {
        public static Anon<T> Create<T>(Func<T> anonFactory)
        {
            return new Anon<T>(anonFactory());
        }

        public abstract void Fire(TContext context);
        public class Anon<T> : SafeAnon<TContext>
        {
            private readonly T _out;

            public delegate void Delayed(TContext context, T anon);

            public Anon(T @out)
            {
                _out = @out;
            }

            public event Delayed UseMe;
            public override void Fire(TContext context)
            {
                UseMe?.Invoke(context, _out);
            }
        }
    }

    public static SafeAnon<SomeContext> Test()
    {
        var sa = SafeAnon<SomeContext>.Create(() => new { AnonStuff = "asdf123" });

        sa.UseMe += (ctx, anon) =>
        {
            ctx.Stuff.Add(anon.AnonStuff);
        };

        return sa;
    }

    public class SomeContext
    {
        public List<string> Stuff = new List<string>();
    }

and then later somwhere else:

    static void Main()
    {
        var anonWithoutContext = Test();

        var nowTheresMyContext = new SomeContext();
        anonWithoutContext.Fire(nowTheresMyContext);

        Console.WriteLine(nowTheresMyContext.Stuff[0]);

    }
user_56881460
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