why delegate must be static?

Question

In code below I must declare method MdrResponseInterpreter static otherwise I have compilation error.

class.... {

    private StandardBuilder _mdrResponseBuilder = 
      new StandardBuilder(MdrResponseInterpreter);

    public static bool MdrResponseInterpreter(DNMessageDeliverer builder, 
                                              DNFieldSet message)
    {
        // .... work
    }

Why? As _mdrResponseBuilder is not static I expect that MdrResponseInterpreter should be able to access this

Answer 1

Because field initializers don't have access to this / instance members. Move the initialization to the constructor if you want access to instance members.

The spec says:

A variable initializer for an instance field cannot reference the instance being created. Thus, it is a compile-time error to reference this in a variable initializer

While your code doesn't explicitly reference this, the method group to delegate conversion does reference this implicitly if the method is an instance member.