I can't invoke an SQL command on multiple threads C#

Question

So i have a method that does an invoke on a datagridview and works fine for the first thread that runs it, however when a second thread tries to utilise the method, the download part of it still functions, however the invoke statement stops working for the first thread and starts to change both

public void ByteTransferResume(int indexResume)
{
    HttpWebRequest req;
    HttpWebResponse resp;
    req = (HttpWebRequest)HttpWebRequest.Create(FileLocationName);
    req.AddRange((int)fileInfoDestination.Length);
    resp = (HttpWebResponse)(req.GetResponse());
    long fileLength = resp.ContentLength;
    FileLocationLength = fileLength;
    using (Stream responseStream = resp.GetResponseStream())
    {
        int iBufferSize = 1024;
        iBufferSize *= 1000;
        using (FileStream saveFileStream = new FileStream(FileDestination, FileMode.Append, FileAccess.Write, FileShare.ReadWrite))
        {
            int iByteSize;
            byte[] downBuffer = new byte[iBufferSize];

            while ((iByteSize = responseStream.Read(downBuffer, 0, downBuffer.Length)) > 0)
            {
                saveFileStream.Write(downBuffer, 0, iByteSize);

                FileInfo fileInfoDestinations = new FileInfo(FileDestination);

                FileDestinationLength = (int)fileInfoDestinations.Length;

                double downloadProgress = ((double)FileDestinationLength / FileLocationLength) * 100;

                // MessageBox.Show(downloadProgress.ToString());

                dgvDownloadInfo.Invoke(new dgvCommandDelegate(DGVCommand), new object[] { $"UPDATE Download_Info SET [Progress] = '{downloadProgress:F2}%' WHERE [File Name] = '{thread1[indexResume].Name}'" });

                //MessageBox.Show(thread1[indexResume].Name);
                //MessageBox.Show(indexResume.ToString());
                // dgvDownloadInfo.Invoke(new dgvConnectionDelegate(DGVConnection));
                Thread.Sleep(10);
            }
        }
    }
}

Is dgvDownloadInfo a control? If so [surely you want .BeginInvoke()](http://stackoverflow.com/questions/229554/whats-the-difference-between-invoke-and-begininvoke) — Alex K., Mar 15 '17 at 15:59
It's been a while since I did C#, but can't you add [Serializable] above the block of code? Might be what you're looking for. — SS_DBA, Mar 15 '17 at 16:04
What is FileDestination? If it is a shared variable, you're overriding the file — VMAtm, Mar 17 '17 at 21:20

score 0 · Answer 1 · answered Mar 15 '17 at 16:11

0

Maybe this will help you:

 public object _lock = new object();
 public void ByteTransferResume(int indexResume)
 {
     lock (_lock)
     {
         HttpWebRequest req;
         //rest of your method         
     }
  }

answered Mar 15 '17 at 16:11

daniell89

1,832
16
28

it didnt work im afraid, thanks anyway, sorry to be a pain im very new to this but i appreciate it all guys :) ill get there eventually!! :) – foreveraphone Mar 15 '17 at 16:40

I can't invoke an SQL command on multiple threads C#

1 Answers1