Question

Delphi has a standard mechanism where one object can be copied from another, paraphrased here as:

class Persistent 
{
    protected AssignError(Persistent source)
    {
       throw new ConvertError("Cannot assign a {0} to a {1}", source.GetType().Name, this.GetType().Name);
    }

    protected virtual AssignTo(Persistent destination)
    {
        destination.AssignError(this);
    }

    public virtual Assign(Persistent source)
    {
       source.AssignTo(this);
    }
}

Does the .NET FCL has a canonical syntax of copying objects between each other?

e.g.:

interface IPersistent
{
   public virtual Assign(Object source);
}

public class User : IPersistent
{
    private Image avatarThumbnail;
    private String name;

    public override Assign(Object source)
    {
       if (source is User)
       {
          this.avatarThumbnail = source.avatarThumbnail;
          this.name = source.Name;
       }
       else if (source is Image)
           avatarThumbnail = (Image)source;
       else if (source is DirectoryEntry)
           name = ((DirectoryEntry) source).Firstname + " " + ((DirectoryEntry) source).Lastname;
       else
           throw new AssignError("Assign from {0}", source.GetType());
    }
}

Yes i just invented a standard IPersistent interface; but is there already a mechanism to copy objects between each other?

Update

Note: i am talking about the opposite of cloning an object.

User originalUser = new User();
User theClone = originalUser.Clone();
theClone.Lastname = "Guyer";

originalUser.Assign(theClone);

Or, i don’t even need to have a clone at all:

User u = new User();
u.Assign(salesOrder); //copy name/e-mail from the sales order

or

SalesOrder s = new SalesOrder();
s.SalesOrderDate = DateTime.Now;
User customer = new Customer("Kirsten");
s.Assign(user); //copy sold-to/ship-to information from the user

Answer 1

The .NET framework has the ICloneable interface:

Supports cloning, which creates a new instance of a class with the same value as an existing instance.

And:

The ICloneable interface contains one member, Clone, which is intended to support cloning beyond that supplied by MemberwiseClone. For more information about cloning, deep versus shallow copies, and examples, see the Object.MemberwiseClone method.

---

Update:

As far as I know, there is nothing equivalent to what you want (standard way to copy some values between different objects) in the BCL.