Creating a shallow copy of structures in C#

.net, c#, clone, deep-copy, shallow-copy

Solution

Your expectation of what a deep copy vs a shallow copy does is not correct. A shallow copy copies all value types, and just the references of reference types. A deep copy copies all value types and all reference types.

So your struct already performs a shallow copy when doing:

MyStruct struct2 = struct1;

This code example (console application) shows, that changing a value of the object in the second struct changes also the value of the object in the first struct, because the object has just been copied by reference:

class Program
{
    static void Main(string[] args)
    {
        Test t1 = new Test();
        t1.i = 1;
        t1.o = new Klasse();
        t1.o.i = 1;

        Test t2 = t1;
        t2.i = 2;
        t2.o.i = 2;

        Console.WriteLine(t1.i.ToString());
        Console.WriteLine(t1.o.i.ToString());
        Console.WriteLine(t2.i.ToString());
        Console.WriteLine(t2.o.i.ToString());
        Console.Read();
    }
}

struct Test
{
    public int i;
    public Klasse o;
}

class Klasse
{
    public int i = 0;
}

Problem

I tried to search for my answer and found them in regards to C and not C# so thought of posting it. My question might be trivial here. As per my understanding (in simple terms) After Copying has completed Shallow Copy -> main and copied object (reference or value type) should point to the same object in memory DeepCopy -> main and copied object (reference or value type) should point to different objects in memory Going ahead with this, I have a structure in C# and trying to make a shallow copy of the same. I tried using "MemberwiseClone" method but I guess it works only for reference types. For value types i think "MemberwiseClone" method will box it into an object and unbox it into a different memory address in the stack. What i have tried is as below. My question is how (if at all possible) can I create a shallow copy of a simple structure? I hope my fundamentals are correct here and not talking rubbish. Please correct me if I am wrong in any of the statements I have made. Regards, Samar ``` struct MyStruct : ICloneable { public int MyProperty { get; set; } public object Clone() { return this.MemberwiseClone();//boxing into object } } private void btnChkStr_Click(object sender, EventArgs e) { MyStruct struct1 = new MyStruct(); struct1.MyProperty = 1; //MyStruct struct2 = struct1; //This will create a deep copy MyStruct struct2 = (MyStruct)(struct1.Clone());//unboxing into structure hence allocating a different memory address struct2.MyProperty = 2; MessageBox.Show(struct1.MyProperty.ToString()); //still showing 1 } ```

Original source