Invoke an extension method on a method without a explicit reference

Question

Is there any way to invoke an extension method on a method, but without a explicit reference?

For example, if I have a extension method:

public static class Extensions {
    public static void FooOn(this Func<string> method) =>
        Console.WriteLine($"Foo on {method()}");
}

I thought maybe I could do something like this, but perhaps not.

class Program {
    private string Bar() => "you"; 
    void Main() => Bar.FooOn();  // won't compile
}

Instead it seems I have to declare a temporary reference:

class Program {
    private string Bar() => "you"; 
    void Main(){
        Func<string> temp = Bar;
        temp.FooOn();
    }
}

So is there any way to invoke an extension method on a method, but without a explicit reference?

Answer 1

No, you can't, as it is a method, which cannot be used with extension methods.

There are several workarounds (.NET Fiddle):

1. As already mentioned in the question, you can create a temporary variable, which references the method:

   Func<string> temp = Bar;
   temp.FooOn();
   

2. You can explicitly cast Bar to a Func<string>:

   static void Main() => ((Func<string>)Bar).FooOn();
   

3. You call the extension method directly, passing Bar as a parameter:

   static void Main() => Extensions.FooOn(Bar);
   

4. You store Bar as a Func<string> variable:

   static Func<string> Bar = () => "you"; 
   static void Main() => Bar.FooOn();