Question

I’m beginning to fall in love with Extension Methods, but I just don’t know how to create an EM only for a determinate Object type.

I have for example:

public static void AddPhoneNumberToContact(this Contact contact, PhoneType type, String number) {     lock (contact)     {         PhoneRow pr = PhoneRow.CreateNew();         pr.SetDefaults();         pr.PtypeIdx = type;         pr.PhoneNumber = number;         contact.Phones.Add(pr);         pr = null;     } } 

My problem is that I want to also Have this method in the Person object, and that is why I named

AddPhoneNumberToContact AddPhoneNumberToPerson 

Is there a way to have AddPhoneNumber and deal with the object that is provided?

or the solution is to have

public static void AddPhoneNumber(this object contact, ... {    ...     if(typeof(Contact) == contact)       ((Contact)contact).Phones.Add(pr);    else if(typeof(Person) == contact)       ((Person)contact).Phones.Add(pr); } 

Thank you.

Answer 1

How about writing two extension methods:

public static void AddPhoneNumber(this Contact contact, PhoneType type); 

and

public static void AddPhoneNumber(this Person person, PhoneType type); 

Looks cleaner to me.

If there’s some common code between the two, extract that into a separate method.