SizeOf

sizeof.cs

using System;
using System.Reflection.Emit;

static class SizeOf<TStruct> where TStruct : struct
{
	public static readonly int Value;
	
	static SizeOf()
	{
		var method = new DynamicMethod("", typeof(int), Type.EmptyTypes);
		var il = method.GetILGenerator();
		il.Emit(OpCodes.Sizeof, typeof(TStruct));
		il.Emit(OpCodes.Ret);
		
		var func = (Func<int>) method.CreateDelegate(typeof(Func<int>));
		Value = func();
	}
}

struct Foo
{
	public int Bar;
	public int Baz;
}

class Program
{
	static void Main()
	{
		Console.WriteLine(SizeOf<Foo>.Value);
	}
}