C# Cloning Classes

Question

I have created a custom Point class in C#, because the regular Point class doesn't have a lot of the functions I need for it. The problem that I face, is that when I create a new custom Point class, and then create another variable to represent that newly created class, they are assigned the same addresses in memory. I remember to change this in C++ you had to use & and *, but in C# I don't know how to do this.

Here's an example of the problem I'm facing

public string Example()
{
   CustomPoint pt = new CustomPoint(0, 0);
   CustomPoint ptbuf = pt;
   ptbuf.X = 100;
   return(pt.X.ToString()); // returns the value of 100, instead of 0, which it should be
}

And this is what should happen, and what does happen with a normal Point class

public string Example2()
{
   Point pt = new Point(0, 0);
   Point ptbuf = pt;
   ptbuf.X = 100;
   return (pt.X.ToString()); // returns the value 0
}

Also, here is the part of the CustomPoint class I've made that isn't working right.

public class CustomPoint
{
    public float X { get; set; }
    public float Y { get; set; }
}

Thanks for your help.

Answer 1

You should make it a struct, not a class. Structs are value types and classes are reference types, which means that when you assign pt to ptbuf, you pass only the reference of the object, not a copy. See https://msdn.microsoft.com/en-us/library/ms173109.aspx for more information on the subject

Answer 2

As Henk states, you should use a struct and make it immutable.

Instead of creating your own CustomPoint class what not just extend the Point class.

public static class PointExtentsions
{
    public static int MyMethod(this Point point) { ... }
}

The above will add MyMethod to any Point .