How to access members of an struct like an array in C#?

Question

Lets say I have a struct with more than hundred elements with complex names. And I am passing a struct of the struct type described to a function using ref, like this:

Answer 1

I will probably burn in hell, but...

Obviously horrible and not recommended and only works if your fields are all ints with default layout...

internal class Program
{
    private struct MyStruct
    {
        //Must be all Int32
        public int Field1, Field2, Field3;
    }

    private static void Main()
    {
        MyStruct str = new MyStruct {Field1 = 666, Field2 = 667, Field3 = 668};

        int[] array = ToArray(str);

        array[0] = 100;
        array[1] = 200;
        array[2] = 300;

        str = FromArray(array);
    }

    private static int[] ToArray(MyStruct str)
    {
        IntPtr ptr = IntPtr.Zero;

        try
        {
            int size = GetInt32ArraySize(str);
            int[] array = new int[size];
            ptr = Marshal.AllocHGlobal(size);
            Marshal.StructureToPtr(str, ptr, true);
            Marshal.Copy(ptr, array, 0, size);
            return array;
        }
        finally
        {
            Marshal.FreeHGlobal(ptr);
        }
    }

    private static MyStruct FromArray(int[] arr)
    {
        IntPtr ptr = IntPtr.Zero;

        try
        {
            MyStruct str = new MyStruct();
            int size = GetInt32ArraySize(str);
            ptr = Marshal.AllocHGlobal(size);
            Marshal.Copy(arr, 0, ptr, size);
            str = (MyStruct)Marshal.PtrToStructure(ptr, str.GetType());
            return str;
        }
        finally
        {
            Marshal.FreeHGlobal(ptr);
        }
    }

    private static int GetInt32ArraySize(MyStruct str)
    {
        return Marshal.SizeOf(str) / Marshal.SizeOf(typeof(Int32));
    }
}