How can I write a Func without Lambde expression?

Question

I am just thinking how to convert this: List.Where(X=>X>5); to non-lambda expression code. I cannot figure out how to get Func working here.

Answer 1

There are two reasonably simple possibilities for creating delegates without using lambda expressions:

• Write a method and use a method group conversion

  private static bool GreaterThan5(int x)
  {
      return x > 5;
  }
  
  ...
  
  var query = list.Where(GreaterThan5);
  

• Use an anonymous method

  var query = list.Where(delegate(int x) { return x > 5; });
  

Neither of those are as clear as using a lambda expression though. For more complicated examples where you actually want to capture local variables, the "write a separate method" version would get a lot more complicated.

Answer 2

While I don't understand the purpose of this, you can do it like this:

bool MyFilterFunction(int x)
{
    return x > 5;
}

Then rewrite your code:

List.Where(MyFilterFunction);