using System;

using System.IO;

using System.Net;

class Program

{

    static void Main(string[] args)

    {

        string ftpServer = "ftp://example.com"; // FTP服務(wù)器地址

        string username = "username"; // FTP登錄用戶名

        string password = "password"; // FTP登錄密碼

        string localFilePath = @"C:\path\to\localfile.txt"; // 本地文件路徑

        string remoteDirectory = "/remote/directory/"; // 遠(yuǎn)程目錄路徑

        string fileName = Path.GetFileName(localFilePath); // 文件名稱

        try

        {

            using (var fileStream = File.OpenRead(localFilePath))

            {

                var requestUriBuilder = new UriBuilder(ftpServer + remoteDirectory + fileName);

                if (!IsRemoteFileExists(requestUriBuilder.ToString(), username, password))

                {

                    UploadWholeFile(requestUriBuilder.ToString(), fileStream, username, password);

                }

                else

                {

                    long uploadedSize = GetUploadedSize(requestUriBuilder.ToString());

                    if (uploadedSize > 0 && uploadedSize < fileStream.Length)

                    {

                        ResumeUploadFromPosition(requestUriBuilder.ToString(), fileStream, uploadedSize, username, password);

                    }

                    else

                    {

                        Console.WriteLine("The file is already fully uploaded.");

                    }

                }

            }

            Console.WriteLine("File upload completed successfully!");

        }

        catch (Exception ex)

        {

            Console.WriteLine($"An error occurred during the file upload process: {ex}");

        }

    }

    private static bool IsRemoteFileExists(string url, string userName, string password)

    {

        var request = (FtpWebRequest)WebRequest.Create(url);

        request.Method = WebRequestMethods.Ftp.ListDirectoryDetails;

        request.Credentials = new NetworkCredential(userName, password);

        try

        {

            using (var response = (FtpWebResponse)request.GetResponse())

            {

                return true;

            }

        }

        catch (WebException)

        {

            return false;

        }

    }

    private static