Implicit Operators and lambdas
c#, delegates, expression, implicit-conversion, lambda
Solution
Your problem is that the C# language does not chain user-defined implicit conversions.
Lambda expressions are untyped expressions that have implicit conversions to the (potentially infinite) set of compatible delegate & expression tree types. (see §6.5 of the spec)
You cannot invoke both that implicit conversion and the user-defined implicit conversion from a delegate type to your own type implicitly.
Instead, you can explicitly create a typed delegate:
Lambda<TIn, TOut> l = new Func<TIn, TOUt>(o => ... );
You could also ask the C# language team to define a syntax for user-defined implicit conversions from method groups or lambdas to any type.
Problem
I'm trying to create a class that takes a lambda and stores it internally. The syntax would be something like: ``` class Lambda<TIn, TOut> { private Expression<Func<TIn, TOut>> expr; private Func<TIn, TOut>> func; public Lambda(Expression<Func<TIn, TOut>> e) { expr = e; } public Lambda(Func<TIn, TOut> f) { func = f; } public static implicit operator Lambda<TIn, TOut>([lambdatype] o) { return new Lambda(o); } } ``` Usage: ``` Lambda<TIn, TOut> l = o => ... ; ``` But I'm having some trouble figuring out the details. I know that a lambda is an anon type until it's assigned to either an expression or a delegate and that I would (I believe) have to use an implicit operator to get the syntax I'm going for, but beyond that I've hit a wall. I can use Expression or Func in my implicit operator if they've already been assigned to a variable like so: ``` Expression<Func<T1, T2>> e = o => ...; Func<T1, T2> f = o => ...; Lambda<T1, T2> l1 = e, l2 = f; ``` But I'd much prefer to just assign the lambda itself and have the class figure out the details.