c# ftp判断远程服务器有没有ABC文件夹如果没有就创建

您可以使用System.Net.FtpWebRequest类来连接到FTP服务器并执行相关操作。以下是一个示例代码，用于检查远程服务器是否存在/ABC文件夹并在不存在时创建它：

using System;
using System.Net;

class Program
{
    static void Main(string[] args)
    {
        string ftpServer = "ftp://your_ftp_server";
        string folderPath = "/ABC";

        if (IsFolderExists(ftpServer, folderPath))
        {
            Console.WriteLine("The folder already exists.");
        }
        else
        {
            if (CreateFolder(ftpServer, folderPath))
            {
                Console.WriteLine("The folder has been created successfully.");
            }
            else
            {
                Console.WriteLine("Failed to create the folder.");
            }
        }
    }

    static bool IsFolderExists(string ftpServer, string folderPath)
    {
        FtpWebRequest request = (FtpWebRequest)WebRequest.Create(ftpServer + folderPath);
        request.Method = WebRequestMethods.Ftp.ListDirectory;
        request.EnableSsl = false;
        request.Credentials = new NetworkCredential("username", "password");

        try
        {
            using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
            {
                return true;
            }
        }
        catch (WebException ex)
        {
            FtpWebResponse response = (FtpWebResponse)ex.Response;
            if (response.StatusCode == FtpStatusCode.ActionNotTakenFileUnavailable)
            {
                return false;
            }
            else
            {
                throw;
            }
        }
    }

    static bool CreateFolder(string ftpServer, string folderPath)
    {
        FtpWebRequest request = (FtpWebRequest)WebRequest.Create(ftpServer + folderPath);
        request.Method = WebRequestMethods.Ftp.MakeDirectory;
        request.EnableSsl = false;
        request.Credentials = new NetworkCredential("username", "password");

        try
        {
            using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
            {
                return true;
            }
        }
        catch (WebException ex)
        {
            throw;
        }
    }
}

在上面的代码中，您需要将"your_ftp_server"替换为您的FTP服务器地址，并将"username"和"password"替换为您的FTP凭据。然后，代码将通过调用IsFolderExists方法来检查指定的文件夹是否存在，如果不存在，则调用CreateFolder方法来创建文件夹。

请确保在使用此代码之前，您已经添加了对System.Net命名空间的引用，并根据您的实际情况进行相应的修改