Question

I thought that to clone a List you would just call:

List<int> cloneList = new List<int>(originalList); 

But I tried that in my code and I seem to be getting effects that imply the above is simply doing:

cloneList = originalList… because changes to cloneList seem to be affecting originalList.

So what is the way to clone a List?

EDIT:

I am thinking of doing something like this:

public static List<T> Clone<T>(this List<T> originalList) where T : ICloneable {     return originalList.ConvertAll(x => (T) x.Clone()); } 

EDIT2:

I took the deep copy code suggested by Binoj Antony and created this extension method:

public static T DeepCopy<T>(this T original) where T : class {     using (MemoryStream memoryStream = new MemoryStream())     {         BinaryFormatter binaryFormatter = new BinaryFormatter();         binaryFormatter.Serialize(memoryStream, original);         memoryStream.Seek(0, SeekOrigin.Begin);         return (T)binaryFormatter.Deserialize(memoryStream);     } } 

EDIT3:

Now, say the items in the List are structs. What then would result if I called?:

List<StructType> cloneList = new List<StructType>(originalList); 

I am pretty sure than I would get a List filled with new unique items, correct?

Answer 1

You can use the below code to make a deep copy of the list or any other object supporting serialization:

Also you can use this for any version of .NET framework from v 2.0 and above, and the similar technique can be applied (removing the usage of generics) and used in 1.1 as well

public static class GenericCopier<T> {     public static T DeepCopy(object objectToCopy)     {         using (MemoryStream memoryStream = new MemoryStream())         {             BinaryFormatter binaryFormatter = new BinaryFormatter();             binaryFormatter.Serialize(memoryStream, objectToCopy);             memoryStream.Seek(0, SeekOrigin.Begin);             return (T) binaryFormatter.Deserialize(memoryStream);         }     } } 

You can call it by using

List<int> deepCopiedList = GenericCopier<List<int>>.DeepCopy(originalList); 

Full code to test if this works:

static void Main(string[] args) {     List<int> originalList = new List<int>(5);     Random random = new Random();     for(int i = 0; i < 5; i++)     {         originalList.Add(random.Next(1, 100));         Console.WriteLine('List[{0}] = {1}', i, originalList[i]);     }     List<int> deepCopiedList = GenericCopier<List<int>>.DeepCopy(originalList);     for (int i = 0; i < 5; i++)         Console.WriteLine('deepCopiedList[{0}] value is {1}', i, deepCopiedList[i]); }