#143 – An Example of Implementing ICloneable for Deep Copies

Here’s an example of implementing ICloneable in two custom classes so that you can use the Clone method to do a deep copy.

To do a deep copy of the Person class, we need to copy its members that are value types and then create a new instance of Address by calling its Clone method.

        public class Person : ICloneable
            public string LastName { get; set; }
            public string FirstName { get; set; }
            public Address PersonAddress { get; set; }

            public object Clone()
                Person newPerson = (Person)this.MemberwiseClone();
                newPerson.PersonAddress = (Address)this.PersonAddress.Clone();

                return newPerson;

The Address class uses MemberwiseClone to make a copy of itself.

        public class Address : ICloneable
            public int HouseNumber { get; set; }
            public string StreetName { get; set; }

            public object Clone()
                return this.MemberwiseClone();

Cloning a Person:

            Person herClone = (Person)emilyBronte.Clone();

About Sean
Software developer in the Twin Cities area, passionate about software development and sailing.

10 Responses to #143 – An Example of Implementing ICloneable for Deep Copies

  1. Dipmalya Majumder says:

    Great example Sean.

  2. Pingback: deep copying userControl | BlogoSfera

  3. David Galehouse says:

    You nailed this one Sean!

  4. Seb C. says:

    Thanks, was very clear and usefull 🙂

  5. Ema C says:

    What if instead of an Address object you had a list of Addresses? How would you copy them all? I was thinking about a for or a foreach but that would impact on performance.

    • Sean says:

      You could use Array.Clone, or if List, do a foreach or implement an extension method like:

      public static IList Clone(this IList listToClone) where T: ICloneable
      return listToClone.Select(item => (T)item.Clone()).ToList();

  6. Dave says:

    Hey Sean,

    Thanks for the example regarding the list above.

    I have a ObservableCollection which has a Children property.
    If I clone the list using the extension you provided, the list is cloned but if I modify any of its children, then the original ObservableCollection is modified as well.

    var clonedList = ObjectCloner.SeanClone(list);

    clonedList[0].Description = “test”; // original list in not affected
    clonedList[0].Children[0].Description = “test” // this affects the original list

    I’m guessing I need some sort of recursion but I’m not getting anywhere :/ Something like:
    var clonedList = _CloneEverything(list);
    Any ideas what the content of _CloneEverything should be?

    Thanks, Dave

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