FtpWebRequest删除指定文件夹内文件的函数代码

以下是使用FtpWebRequest删除FTP服务器上指定文件夹内文件的代码示例：

public static void DeleteFTPDirectory(string url, NetworkCredential credentials)
{
    FtpWebRequest request = (FtpWebRequest)WebRequest.Create(url);
    request.Credentials = credentials;
    request.Method = WebRequestMethods.Ftp.ListDirectory;

    using (WebResponse response = request.GetResponse())
    {
        using (StreamReader reader = new StreamReader(response.GetResponseStream()))
        {
            string line = reader.ReadLine();
            while (!string.IsNullOrEmpty(line))
            {
                string fileUrl = url + "/" + line;
                if (line != "." && line != "..")
                {
                    FtpWebRequest deleteRequest = (FtpWebRequest)WebRequest.Create(fileUrl);
                    deleteRequest.Credentials = credentials;
                    deleteRequest.Method = WebRequestMethods.Ftp.DeleteFile;
                    deleteRequest.GetResponse();
                }
                line = reader.ReadLine();
            }
        }
    }
}

调用此方法时，需要传入FTP服务器的URL和凭据。注意，此方法将删除指定文件夹内的所有文件，但不会删除文件夹本身。如果需要删除文件夹本身，可以使用WebRequestMethods.Ftp.RemoveDirectory方法。