如何在c# .net标准中动态加载原生动态链接库？

using System.Runtime.InteropServices;

public class NativeMethods
{
    [DllImport("kernel32.dll")]
    public static extern IntPtr LoadLibrary(string dllToLoad);

    [DllImport("kernel32.dll")]
    public static extern IntPtr GetProcAddress(IntPtr hModule, string procedureName);

    [DllImport("kernel32.dll")]
    public static extern bool FreeLibrary(IntPtr hModule);

    public delegate int MyFunctionDelegate(int param);

    public static void Main()
    {
        IntPtr pDll = LoadLibrary("MyNativeLibrary.dll");

        if (pDll == IntPtr.Zero)
        {
            Console.WriteLine("Failed to load dll");
            return;
        }

        IntPtr pAddressOfFunctionToCall = GetProcAddress(pDll, "MyFunction");

        if (pAddressOfFunctionToCall == IntPtr.Zero)
        {
            Console.WriteLine("Failed to find function");
            FreeLibrary(pDll);
            return;
        }

        MyFunctionDelegate myFunctionDelegate = (MyFunctionDelegate)Marshal.GetDelegateForFunctionPointer(pAddressOfFunctionToCall, typeof(MyFunctionDelegate));
        int result = myFunctionDelegate(1);
        Console.WriteLine("The result is: " + result);
        FreeLibrary(pDll);
    }
}