Convert anonymous type to new C# 7 tuple type

Question

The new version of C# is there, with the useful new feature Tuple Types:

public IQueryable Query();

public (int id, string name) GetSomeIn         


        

Answer 1

Note for anyone on a lower version of .NET: If you are on a lower version of .NET than 4.7.2 or .NET Core, you should use Nuget Package Manager to install System.ValueTuple to your project.

Then, here's an example of getting a tuple from a Linq to SQL query:

var myListOfTuples = (from record1 in myTable.Query()
                     join record2 in myTable2.Query() on record1.Id = record2.someForeignKey
                     select new {record1, record2}).AsEnumerable()
                     .select(o => (o.record1, o.record2))
                     .ToList()

That ran for me, however, after check-in, I got a build failure...read on.

For even more fun and games, I unfortunately had an earlier version of C# on my build server for some reason. So I had to go back because it didn't recognize the new tuple format on the .select(o => (o.record1, o.record2)) line (specifically that it would be a tuple because of the parenthesis around o.record1 and o.record2). So, I had to go back and kind of finagle it a bit more:

var myListOfAnonymousObjects = (from record1 in myTable.Query()
                     join record2 in myTable2.Query() on record1.Id = record2.someForeignKey
                     select new {record1, record2}).ToList()

var myTuples = new List>();
foreach (var pair in myListOfAnonymousObjects)
{
    myTuples.Add(pair.record1, pair.record2);
}
return myTuples;