File being used by another process error

Question

Can anyone tell me how to get rid of the error

The process cannot access the file because it is being used by another process

Here is my code

if (!File.Exists(FlagFilePath))
{
    Debug.WriteLine("Trying to download sales data file ");

    SessionOptions sessionOptions = new SessionOptions
    {
        Protocol = Protocol.Sftp,
        HostName = ConfigurationManager.AppSettings["SFTPDomain"],
        UserName = ConfigurationManager.AppSettings["SFTPUser"],
        Password = ConfigurationManager.AppSettings["SFTPPass"],
        PortNumber = Convert.ToInt32(ConfigurationManager.AppSettings["SFTPPortNumber"]),
        GiveUpSecurityAndAcceptAnySshHostKey = true,

    };

    using (Session session = new Session())
    {

        //Attempts to connect to your SFtp site
        session.Open(sessionOptions);

        //Get SFtp File
        TransferOptions transferOptions = new TransferOptions();
        transferOptions.TransferMode = TransferMode.Binary; //The Transfer Mode - Automatic, Binary, or Ascii 
        transferOptions.FilePermissions = null;  //Permissions applied to remote files; 
        transferOptions.PreserveTimestamp = false;  //Set last write time of destination file 
        //to that of source file - basically change the timestamp to match destination and source files.    
        transferOptions.ResumeSupport.State = TransferResumeSupportState.Off;
        //SFTP File Path
        Sftp_RemotePath = ConfigurationManager.AppSettings["SFTPFileName"].ToString();
        //Delete File if Exist
        if (System.IO.File.Exists(FilePath))
        {
            System.IO.File.Delete(FilePath);
        }
        //the parameter list is: remote Path, Local Path with filename 
        TransferOperationResult transferOperationResult = session.GetFiles(Sftp_RemotePath, FilePath , false, transferOptions);

        //Throw on any error 
        transferOperationResult.Check();
        Debug.WriteLine("Downloaded fresh sales data file!");
    }
}

I am using MVC and have two controllers which access this class. When I run the controllers one at a time then it works fine but when I run both controllers together then I get this error in one of the controller:

WinSCP.SessionRemoteException: Can't create file 'D:\TESTING\SFTP\Data.csv'. ---> WinSCP.SessionRemoteException: System Error.
  Code: 32.
The process cannot access the file because it is being used by another process
   --- End of inner exception stack trace ---
   at WinSCP.OperationResultBase.Check()
   at JetStarAPI.Models.SFTPClient.DownloadFile(String FilePath) in D:\TESTING\SFTP\Models\SFTPClient.cs:line 65}

I am getting this error after this line

 transferOperationResult.Check();

If I change the name of the file here

   TransferOperationResult transferOperationResult = session.GetFiles(Sftp_RemotePath, FilePath+Path.GetRandomFileName() , false, transferOptions);

It works fine and save the file with random file name but I want to pass my FileName. How to solve this?

Answer 1

static bool IsDownloadInProgress = false;

public static string DownloadFile(string FilePath)
{
    string SalesStatus = "ok";
    try
    {
        if (!File.Exists(FlagFilePath) &&  !IsDownloadInProgress)
        {
            Debug.WriteLine("Trying to download sales data file ");

            SessionOptions sessionOptions = new SessionOptions
            {
                Protocol = Protocol.Sftp,
                HostName = ConfigurationManager.AppSettings["SFTPDomain"],
                UserName = ConfigurationManager.AppSettings["SFTPUser"],
                Password = ConfigurationManager.AppSettings["SFTPPass"],
                PortNumber = Convert.ToInt32(ConfigurationManager.AppSettings["SFTPPortNumber"]),
                GiveUpSecurityAndAcceptAnySshHostKey = true,
            };

            using (Session session = new Session())
            {
                //Attempts to connect to your SFtp site
                session.Open(sessionOptions);

                //Get SFtp File
                TransferOptions transferOptions = new TransferOptions();
                transferOptions.TransferMode = TransferMode.Binary; //The Transfer Mode - Automatic, Binary, or Ascii 
                transferOptions.FilePermissions = null;  //Permissions applied to remote files; 
                transferOptions.PreserveTimestamp = false;  //Set last write time of destination file 
                //to that of source file - basically change the timestamp to match destination and source files.    
                transferOptions.ResumeSupport.State = TransferResumeSupportState.On;
                //SFTP File Path
                Sftp_RemotePath = ConfigurationManager.AppSettings["SFTPFileName"].ToString();
                //Delete File if Exist
                if (System.IO.File.Exists(FilePath))
                {
                    System.IO.File.Delete(FilePath);
                }
                //Throw on any error 
                session.FileTransferred += OnFileTransferComplete;
                IsDownloadInProgress = true;
       
                // the parameter list is: remote Path, Local Path with filename 
                session.GetFiles(Sftp_RemotePath,FilePath,false,  transferOptions).Check();
              
                session.Dispose();
                Debug.WriteLine("Downloaded fresh sales data file!");
            }
        }
    }
    catch (Exception ex)
    {
        string _errorMsg = "";
        // Setting Sales Status values
        if (ex.InnerException != null)
        {
            if (ex.InnerException.Message.Contains("Authentication failed"))
            {
                _errorMsg = ex.InnerException.Message;
                Debug.WriteLine("wrong username/password");
                SalesStatus = "2";
            }
            else if (ex.InnerException.Message.Contains("No such file or directory"))
            {
                _errorMsg = ex.InnerException.Message;
                Debug.WriteLine("File is not Available");
                SalesStatus = "3";
            }
        }
        else
        {
            _errorMsg = ex.Message;
            Debug.WriteLine("General SFTP Error");
            SalesStatus = "4";
        }

        //Create log error file
        if (!File.Exists(FlagFilePath))
        {
            // create SFTP LocalErrorFlag
            Debug.WriteLine("Creating SFTP flag file");
            System.IO.File.WriteAllText(FlagFilePath, "SFTP Error: " + _errorMsg);
        }
        else
        {
            Debug.WriteLine("SFTP error Flag file already exists");
        }
    }
    return SalesStatus;
}

private static void OnFileTransferComplete(object sender, TransferEventArgs e)
{
    IsDownloadInProgress = false;
    ((Session)sender).FileTransferred -= OnFileTransferComplete;
}