需要使用win32 api来复制c#中的文件 - 我该怎么做？

using System;
using System.IO;
using System.Runtime.InteropServices;

class FileCopyExample
{
    [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
    static extern bool CopyFile(string lpExistingFileName, string lpNewFileName, bool bFailIfExists);

    static void Main()
    {
        string sourceFile = "source.txt";
        string destinationFile = "destination.txt";

        try
        {
            if (!File.Exists(sourceFile))
            {
                Console.WriteLine("Source file does not exist.");
                return;
            }

            if (File.Exists(destinationFile))
            {
                Console.WriteLine("Destination file already exists.");
                return;
            }

            if (CopyFile(sourceFile, destinationFile, false))
            {
                Console.WriteLine("File copied successfully.");
            }
            else
            {
                Console.WriteLine("Error copying file: {0}", Marshal.GetLastWin32Error());
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error: " + ex.Message);
        }
    }
}