Question

I was wondering if it is possible to add multiple generic constraints?

I have an Add method that takes an Object (Either Email, Phone or Address), so i was thinking something like:

public void Add<T>(T Obj) 
    where T : Address
    where T : Email
    where T : Phone
{
    if (Obj is Address)
        m_Address.Add(Obj as Address);
    else if (Obj is Email)
        m_Email.Add(Obj as Email);
    else
        m_Phone.Add(Obj as Phone);
}

But I keep getting:

"A constraint clause has already been specified for type parameter 'T'. All of the constraints for a type parameter must be specified in a single where clause."

Answer 1

You can’t do that. Why not just have three methods and let the compiler do the hard work for you?

public void Add(Address address) { m_Address.Add(address); }
public void Add(Email email) { m_Email.Add(email); }
public void Add(Phone phone) { m_Phone.Add(phone); }