Search code examples
c#entity-frameworklinq

LINQ query .ToDictionary with Tuple int key

I'm wondering if is it possible to do a linq query like this:

Dictionary<(int,int), object)> entity = _context.Table.ToDictionary((i => i.IDOrigin, i.IDDestiny), o => o);

I know that it's possible with an unique key .ToDictionay(i => i.Key, o => o.Value); but in this case this table has a double PK and I need both as keys.

Thank you.

Solution

  • You just need to tweak your call a bit:

    _context.Table.ToDictionary(i => (i.IDOrigin, i.IDDestiny), o => o)

    All I've moved is the brackets: you still want i as a regular lambda expression parameter, but you want the result of the lambda to be a tuple literal, which is the (i.IDOrigin, i.IDDestiny) part.

    Note that the o => o part is unnecessary - if you don't specify a lambda expression for projecting from a source element to a value, ToDictionary uses the source element as the value. So you can use:

    _context.Table.ToDictionary(i => (i.IDOrigin, i.IDDestiny))