How to propagate an anonymous type variable from using scope to outside?

Question

// var outterResult = null;

using (var ctx = new TIS2APPContext())
{
    var results = (
        from t in (
            from route in ctx.ROUTEs
            join rstop in ctx.RSTOPs on route.ROUTEID equals rstop.ROUTEID
            join stop in ctx.STOPs on rstop.STOPID equals stop.STOPID
            select new { Route = route, RStop = rstop, Stop = stop }
        ).ToArray()
        group new { RStop = t.RStop, Stop = t.Stop } by t.Route into g
        select new { Route = g.Key, Stops = g.ToArray() }
    ).ToArray();
}

Let say I have a complicated LINQ results in a using scope. Is there a way to get it escape to the outside world? The point is anonymous type, I am not going to create an actual class in this case.

Thanks in advance.

just map to custom class objects? or inject db context to a larger scope, so you are not restritcted with using block — Yehor Androsov, Feb 17 '21 at 04:35
You are having a toarray in the end. You can have a variable with Array type outside using and then assign the result. — T.kowshik Yedida, Feb 17 '21 at 04:36
Can you show what you want to do with it? The `using` doesn't really have anything to do with the issue as you can hoist it. — Aluan Haddad, Feb 17 '21 at 04:37
@YegorAndrosov custom class object means I need to create a class, then it is not a anonymous class anymore... db context hold db connection, which should be closed once I get my job done — mannok, Feb 17 '21 at 04:39
@T.kowshikYedida The question is... what should the type be in the Array? — mannok, Feb 17 '21 at 04:40
@AluanHaddad This is Entity Framework. Codes inside `using` have ability to connect to DB — mannok, Feb 17 '21 at 04:40
This may be what you are looking for - https://stackoverflow.com/questions/6624811/how-to-pass-anonymous-types-as-parameters — Alexei Levenkov, Feb 17 '21 at 04:56
@mannok, I meant the Array class like this https://dotnetfiddle.net/DB3bAL. — T.kowshik Yedida, Feb 17 '21 at 06:30

score 0 · Answer 1 · answered Feb 17 '21 at 04:42

You can not declare type for anonymous object, but you can give it a hint if you use anonymous objects with the same fields in the outer scope. Fields can have dummy values.

You are still limited to a scope of the executing method, though. To use it outside of the method you'll need to map result to tuples, if you don't want to use classes

var results = new[]
{
    new { Route = string.Empty, Stops = new List<string>() }
};

using (var db = new DbContext(""))
{
    results = (from o in db.Set<object>()
                    select new { Route = string.Empty, Stops = new List<string>() }
                    ).ToArray();
}

How to propagate an anonymous type variable from using scope to outside?

1 Answers1