Question

I have 2 classes Customer and Person(share exactly the same properties and these properties should be filled in by a request

I would like to write a generic method like

    //Usage Customer myCustomer =CreateCustomerOrPerson<Customer>(myRequest)
    //Usage Person myPerson =CreateCustomerOrPerson<Person>(myRequest)
    public static T FillPropertiesOfCustomerOrPerson<T>(Request request)
    {
       //not sure how I would I do it to fill the properties.
      // T a = default(T);

      //a.Name=request.Name;
      //a.Surname=request.Surname;

      // if (a is Customer)
       //{
          //?
      /// }
       return (T)a;
    } 

    How would you write this generic method to avoid having 2 methods (one for customer and one for person)?

Edit

I have no control over these classes. I just need to fill the properties and I was wondering if I could write a generic method rather than 2 specific ones.

Answer 1

Given the requirements, your options are somewhat limited. If you don’t want to make use of the dynamic keyword (due to .NET version or whatever), you could do this old-style and use reflection. A possible implementation of that follows:

private const string PROP_NAME = "Name";
private const string PROP_SURNAME = "Surname";

public static T FillPropertiesOfCustomerOrPerson<T>(Request request)
    where T : new()
{
    if (typeof(T) != typeof(Person) && typeof(T) != typeof(Customer))
    {
        throw new Exception(
            string.Format("{0} is not a supported type.", typeof(T).Name)
        );
    }

    PropertyInfo name = typeof(T).GetProperty(PROP_NAME);
    PropertyInfo surname = typeof(T).GetProperty(PROP_SURNAME);

    T t = new T();

    name.SetValue(t, request.Name, null);
    surname.SetValue(t, request.Surname, null);

    return t;
}

Optionally, you could remove the where T : new() and replace the instantiation code with something like this:

T t = (T)Activator.CreateInstance(typeof(T));