Replace object instance with another in C#

Question

In this question I would like to find out if and how this is possible. This technique would seem extremely bad practice but it seems that the API (UnityEditor) that I am using,

Answer 1

Since an object state is defined by field values, you can copy memory, containing field values, from one object to another, effectively "replacing" it:

public static void Replace(T x, T y)
    where T : class
{
    // replaces 'x' with 'y'
    if(x == null) throw new ArgumentNullException("x");
    if(y == null) throw new ArgumentNullException("y");

    var size = Marshal.SizeOf(typeof(T));
    var ptr = Marshal.AllocHGlobal(size);
    Marshal.StructureToPtr(y, ptr, false);
    Marshal.PtrToStructure(ptr, x);
    Marshal.FreeHGlobal(ptr);
}

Note that this code requires [StructLayout(LayoutKind.Sequential)] (or LayoutKind.Explicit) attribute defined for a class.