如何从C/C++调用.NET程序集？

#using<System.dll>
using namespace System;

using namespace System;
using namespace System.Data;
using namespace System.IO;
using namespace System.Runtime.InteropServices;

using System;
using System.Data;
using System.IO;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace MyProject
{
    public partial class Form1 : Form
    {
        [STAThread]
        public static int GetHello()
        {
            string hello = "Hello, world! My name is .NET!";
            return hello.Length;
        }
    }
}

#include<iostream>
#using<System.dll>
#using<System.reflection.dll>
using namespace System::Reflection;

int main()
{
    Type^ type;
    MethodInfo^ methodInfo;

    type = Type::GetType("MyProject.Form1");
    methodInfo = type->GetMethod("GetHello");
    int result = methodInfo->Invoke(NULL, NULL);
    std::wcout << "Length of the string: "<< result<< std::endl;

    return 0;
}