問題描述

我創(chuàng)建了 FTP 代碼來傳輸文件.此代碼工作正常，但有時會導(dǎo)致錯誤 500.確切的錯誤是 -

I created FTP code to transfer files. This code works fine except that it sometimes causes an error 500. The exact error is -

Error: System.Reflection.TargetInvocationException: Exception has 
been thrown by the target of an invocation. 
---> System.Net.WebException: The remote server returned an error: 
(500) Syntax error, command unrecognized.
   at System.Net.FtpWebRequest.CheckError()
   at System.Net.FtpWebRequest.SyncRequestCallback(Object obj)
   at System.Net.CommandStream.Abort(Exception e)
   at System.Net.FtpWebRequest.FinishRequestStage(RequestStage stage)
   at System.Net.FtpWebRequest.GetRequestStream()
   at ST_772dn22cj49ndfddatee.csproj.ScriptMain.Main()
   --- End of inner exception stack trace --- 

我注意到在加載最大文件(即大約 290 KB)時會發(fā)生錯誤.所有其他文件都少于此，我對它們也不例外.我不知道為什么會這樣.誰能告訴我為什么?

I noticed that the error occurs when the biggest file is loaded, ie about 290 KB. All other files are less than this and i get no exception for them. I don't know why this happens. Can someone tell me why ?

順便說一句，如果您發(fā)現(xiàn)我的代碼有一些改進(jìn)空間或邏輯錯誤，請同時提及.我并不是真的在尋找代碼審查，但它是受歡迎的.

As an aside, in case you notice some room for improvement in my code or logical error, then please mention that as well. I am not really looking for code reviews, but its welcome.

public void Main()
{

    Boolean conditions = true;

    if(conditions == true)
    {
    string fileLocation = "my windows directory";
    string fileName = "fileName.extension";

    string ftpFolder = @"/ftpFolder/";
    Boolean ftpMode = true; //passive or active. True = passive 
    string ftpPassword = "password";
    int ftpPort = 21;// the default
    string ftpServerName = "server name";
    string ftpUserName = "user name";

    //Create an object to communicate with the server.
    string ftpRequestString = "ftp://" + ftpServerName + ":" 
    + ftpPort + ftpFolder + fileName; 

    try{

    FtpWebRequest request = 
    (FtpWebRequest)WebRequest.Create(ftpRequestString);
    request.Method = WebRequestMethods.Ftp.UploadFile;

    request.Credentials = new NetworkCredential(ftpUserName, ftpPassword);

    //Set mode
    if(ftpMode == true){
        request.UsePassive = true;
    }

    //Copy the file to the request.

    string filePath = @fileLocation + "\" + fileName;
    StreamReader sourceStream = new StreamReader(filePath);
    byte[] fileContents = Encoding.UTF8.GetBytes(sourceStream.ReadToEnd());
    sourceStream.Close();
    request.ContentLength = fileContents.Length;

    Stream requestStream = request.GetRequestStream();
    requestStream.Write(fileContents, 0, fileContents.Length);
    requestStream.Close();

    FtpWebResponse response = (FtpWebResponse)request.GetResponse();

    response.Close();

    }
     catch (WebException ex)
     {
        MessageBox.Show(ex.Message);

     }//try-catch

    }

}//main

推薦答案

在閱讀您的問題時，我懷疑這與將 KeepAlive 設(shè)置為 有關(guān)(或可以通過以下方式糾正)錯誤.看著 SO - 這個問題引用了同樣的問題并指出它:https://stackoverflow.com/a/2071374/1803682

request.KeepAlive = false;

request.Timeout = -1;