?
Solved

clone of an inherited generic list

Posted on 2010-08-27
5
Medium Priority
?
731 Views
Last Modified: 2013-11-08
I have a class "NavigationElement", where I implemented a clone method.

Then I have a generic List that inherits from a list of this objects (NavigationElement)

public class NavigationElementsList<NavigationElement> : List<NavigationElement>, ICloneable
...
in this list I also implemented the
   public Object Clone()
        {
            return this.MemberwiseClone();
        }

now I need to call the FindAll method in an istance of this NavigationElementsList<NavigationElement>, but this is not possible because the returned type is not the same as the generic List<T>.
I need to have a deep copy of the list because I'm going to change the values of the properties and this will cause a change in the referenced items in  the original list<T> that I want to avoid.

This also won't work:
 public NavigationElementsList<T> FindAll(Predicate<T> match)
        {
            return base.FindAll(match);
        }

Any suggestions?
0
Comment
Question by:LorenzoB
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
5 Comments
 

Author Comment

by:LorenzoB
ID: 33543064
Actually resolved in this way (maybe useful for some other).
 public NavigationElementsList<NavigationElement> FindAll(Predicate<NavigationElement> match)
        {
            NavigationElementsList<NavigationElement> navCopyOfList = new NavigationElementsList<NavigationElement>();
            navCopyOfList.AddRange(base.FindAll(match));
            return navCopyOfList;
        }
0
 
LVL 31

Expert Comment

by:MlandaT
ID: 33543074
0
 

Author Comment

by:LorenzoB
ID: 33543110
The problem is in the FindAll method and the type that it returns.
Thank you anyway
0
 
LVL 8

Accepted Solution

by:
Gururaj Badam earned 2000 total points
ID: 33579507
In the first place why do you want to inherit from List<T>. I suggest you to write an extension method instead to add your clone method

say like

public T Clone<T>(this List<T> _list)
        {
            return _list.MemberwiseClone(); // Or something like this
        }
0
 

Author Comment

by:LorenzoB
ID: 33581765
To answer to your question, I needed to Inherit from a List<T> because I want to have the FindAll and the Clone (DeepCopy not Shallow).

Your suggestion was indeed helpful.

MemberwiseClone() cannot be called by an extension method of a generics list because it is a private member.
So I did a sort of implementation of the MemberwiseClone.
In the following extract of code are the Extension methods. Maybe could be better written...
The class NavigationElement inherits from ICloneable and implements the Clone() method.

In this way I avoid to create a new Class that inherits from List<NavigationElement>, because the implementation of the Extension Methods.

Thank You
 public static class ListExtensions
        {
            public static object Clone<T>(this List<NavigationElement> list)
            {
                return list.MemberwiseClone<T>();               
            }

            public static List<NavigationElement> MemberwiseClone<T>(this List<NavigationElement> list)
            {
                List<NavigationElement> newList = new List<NavigationElement>();
                foreach (NavigationElement navElem in list)
                {
                    newList.Add((NavigationElement)navElem.Clone());
                }
                return newList; 
            }
        }

Open in new window

0

Featured Post

NEW Veeam Agent for Microsoft Windows

Backup and recover physical and cloud-based servers and workstations, as well as endpoint devices that belong to remote users. Avoid downtime and data loss quickly and easily for Windows-based physical or public cloud-based workloads!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction Hi all and welcome to my first article on Experts Exchange. A while ago, someone asked me if i could do some tutorials on object oriented programming. I decided to do them on C#. Now you may ask me, why's that? Well, one of the re…
Entity Framework is a powerful tool to help you interact with the DataBase but still doesn't help much when we have a Stored Procedure that returns more than one resultset. The solution takes some of out-of-the-box thinking; read on!
This tutorial will teach you the special effect of super speed similar to the fictional character Wally West aka "The Flash" After Shake : http://www.videocopilot.net/presets/after_shake/ All lightning effects with instructions : http://www.mediaf…
Have you created a query with information for a calendar? ... and then, abra-cadabra, the calendar is done?! I am going to show you how to make that happen. Visualize your data!  ... really see it To use the code to create a calendar from a q…
Suggested Courses

743 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question