遠程服務器返回錯誤：（421）服務不可用，關閉控制連接

Question

我正在運行此代碼以通過ftp將本地文件傳輸到另一臺服務器。問題是我正在定期收到錯誤遠程服務器返回錯誤：（421）服務不可用，關閉控制連接。代碼是否存在問題，是更快速傳輸文件的更好方式。所有的文件都需要被轉移，所以我想了一個while循環，並捕獲錯誤，直到文件夾中的所有文件都被轉移。這是我得到的週期性錯誤：

foreach (FileInfo file in files) 
{ 
    try 
    { 
     // Get the object used to communicate with the server. 
     FtpWebRequest request = 
      (FtpWebRequest) 
       WebRequest.Create(String.Format("{0}{1}/{2}", Host, destinationPath, 
        file.Name)); 
     request.Method = WebRequestMethods.Ftp.UploadFile; 
     request.KeepAlive = false; 
     /* 20 mins timeout */ 
     request.Timeout = 1200000; 
     request.ReadWriteTimeout = 1200000; 

     // This example assumes the FTP site uses anonymous logon. 
     request.Credentials = new NetworkCredential(Username, Password); 

     // Copy the contents of the file to the request stream. 
     byte[] fileContents = File.ReadAllBytes(file.FullName); 

     request.ContentLength = fileContents.Length; 

     using (Stream requestStream = request.GetRequestStream()) 
     { 
      requestStream.Write(fileContents, 0, fileContents.Length); 
     } 

     //using (FtpWebResponse response = (FtpWebResponse) request.GetResponse()) 
     //{ 

     //} 

     if (deleteSourcePath) 
     { 
      File.Delete(file.FullName); 
     } 
    } 
    catch (Exception ex) 
    { 
     // Log.Warn("Error Moving Images", ex.Message); 
    } 
} 

Answer 1

調用關閉FtpWebResponse對象。這將釋放關聯的端口。

FtpWebResponse response = (FtpWebResponse) request.GetResponse(); 
// ... 
finally 
{ 
    if (response != null) 
    { 
     response.Close(); 
    } 
}