ToLookup with multiple keys

Question

Is there a way to require multiple keys for the .ToLookup function provided by LINQ?

I will admit that this seems non-intuitive at first, and I\'m expecting

Answer 1

Although not what you really want, but will do the job just fine:

var r = set.ToLookup(x => new { x.StringProp, x.IntProp });
var f = r[ new { StringProp = "a", IntProp = 1 } ].First();