copy a class, C#

Question

Is there a way to copy a class in C#? Something like var dupe = MyClass(original).

Answer 1

Not any straightforward way that will always work. If your class is [Serializable] or implements ISerializable, you can do a roundtrip serialization to create an identical copy. The same works for [DataContract]

If you only want a shallow copy, you can try Object.MemberwiseClone(). It's a protected method though, and you can only use it from within the class.

If you're lucky, the class implements ICloneable and you can just call the Clone() method.

Answer 2

Not all classes have this functionality. Probably, if a class does, it provides a Clone method. To help implement that method for your own classes there's a MemberwiseClone protected method defined in System.Object that makes a shallow copy of the current instance (i.e. fields are copied; if they are reference types, the reference will point to the original location).

Answer 3

If your class has just got properties, you could do something like this:

SubCentreMessage actual;
actual = target.FindSubCentreFullDetails(120); //for Albany
SubCentreMessage s = new SubCentreMessage();

//initialising s with the same values as 
foreach (var property in actual.GetType().GetProperties())
{
    PropertyInfo propertyS = s.GetType().GetProperty(property.Name);
    var value = property.GetValue(actual, null);
    propertyS.SetValue(s, property.GetValue(actual, null), null);
}

If you have fields and methods, I am sure you can recreate them in new class using reflections. Hope this helps

Answer 4

How about something like:

public class MyClass 
{
    int i;
    double d;
    string something;

    public MyClass(int i, double d) {}

    public MyClass Clone()
    {
        return (new MyClass(i, d));
    }
}

Or if you also need to copy something else not usually known when constructing a new object:

    public MyClass CloneMore()
    {
        MyClass obj = new MyClass(i, d);
        obj.something = this.something;
        return (obj);
    }

Call using:

MyClass us = them.Clone();

~~~

Answer 5

Some reasonable solutions here serializing is a valid way to go about it as well as a clone method for each class.. Whipped this up and It seems to work for the few tests i did on it

using System.Reflection; using System.Text.StringBuilder();

public static T CopyClass2<T>(T obj){
    T objcpy = (T)Activator.CreateInstance(typeof(T));
    obj.GetType().GetProperties().ToList()
    .ForEach( p => objcpy.GetType().GetProperty(p.Name).SetValue(objcpy, p.GetValue(obj)));
    return objcpy;

}

And here is the more verbose version I suppose, above suggests you understand Lambda Expressions which isn't common. If you respect readability (Which is totally valid) more I would use below

public static T CopyClass<T>(T obj)
{
    T objcpy = (T)Activator.CreateInstance(typeof(T));
    foreach (var prop in obj.GetType().GetProperties())
    {
        var value = prop.GetValue(obj);
        objcpy.GetType().GetProperty(prop.Name).SetValue(objcpy, value);
    }
    return objcpy;

}

Use this method to list out property's to see if it copied to new reference.. simple it does not list properties of none primitives(structured types).. so you will get a class name

public static string ListAllProperties<T>(T obj)
{
        StringBuilder sb = new System.Text.StringBuilder();
        PropertyInfo[] propInfo = obj.GetType().GetProperties();
        foreach (var prop in propInfo)
        {
            var value = prop.GetValue(obj) ?? "(null)";
            sb.AppendLine(prop.Name + ": " + value.ToString());
        }
        return sb.ToString();
}

Answer 6

How about with JSON?

You can get JSON package from : https://www.nuget.org/packages/Newtonsoft.Json/

using Newtonsoft.Json;
public static List<T> CopyAll<T>(this List<T> list) {
  List<T> ret = new List<T>();
  string tmpStr = JsonConvert.SerializeObject(list);
  ret = JsonConvert.DeserializeObject<List<T>>(tmpStr);
  return ret;
}