How to convert an Expression> to a Predicate

Question

I have a method that accepts an Expression> as a parameter. I would like to use it as a predicate in the List.Find() method, but I can\'t

Answer 1

I'm not seeing the need for this method. Just use Where().

 var sublist = list.Where( expression.Compile() ).ToList();

Or even better, define the expression as a lambda inline.

 var sublist = list.Where( l => l.ID == id ).ToList();

Answer 2

Another options which hasn't been mentioned:

Func<T, bool> func = expression.Compile();
Predicate<T> predicate = new Predicate<T>(func);

This generates the same IL as

Func<T, bool> func = expression.Compile();
Predicate<T> predicate = func.Invoke;

Answer 3

Func<T, bool> func = expression.Compile();
Predicate<T> pred = t => func(t);

Edit: per the comments we have a better answer for the second line:

Predicate<T> pred = func.Invoke;