Update datagridview from background thread

Question

I am invoking Method from the UI, method takes long time to finish so it freeze the UI and prevent user form knowing what's happening.

I am trying to update column (status) at 'datagridview' to feedback user on UI to let him know which ip is connected and which one is not yet, but as I said before UI freeze until the method is finished.

One of the suggestion was to use thread and I did that, but my problem was not solved so did I do something in correctly?

    public void PatchUpdates()
    {
        try
        {
            foreach (DataGridViewRow OfficeListRow in DGV_OfficeList.Rows)
            {
                string OfficeIPAddress = OfficeListRow.Cells[3].Value.ToString();

                foreach (DataGridViewRow FileListRow in DGV_FileList.Rows)
                {
                    string SoruceFileNamePath = FileListRow.Cells[4].Value.ToString();
                    string DestinationFileNamePath = @"\\" + OfficeIPAddress + @"\usb1_1\test\" + Path.GetFileName(SoruceFileNamePath);

                    Thread foregroundthread = new Thread(() => CheckOffice(OfficeIPAddress));
                    foregroundthread.Start();

                    //check if connection to remote server is available
                    if (CheckOffice(OfficeIPAddress) == 1)
                    {
                        DGV_OfficeList[4, DGV_OfficeList.CurrentCell.RowIndex].Value = "Connected";
                        //file.copy(sorucefilenamepath, destinationfilenamepath, true); //copy files...
                    }
                    else if (CheckOffice(OfficeIPAddress) == 0)
                    {
                        DGV_OfficeList[4, DGV_OfficeList.CurrentCell.RowIndex].Value = "disconnected";
                    }
                }
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }

ping method

    public int CheckOffice(string _ipAddress)
    {
        int timeout = 120;
        string data = "PingTestData";
        byte[] buffer = Encoding.ASCII.GetBytes(data);

        Ping PingSender = new Ping();
        PingOptions options = new PingOptions();

        options.DontFragment = true;

        PingReply reply = PingSender.Send(_ipAddress, timeout, buffer, options);

        if (reply.Status == IPStatus.Success)
        {
            return 1;
        }
        else
        {
            return 0;
        }
    }

Answer 1

At the moment you are calling CheckOffice three times, once in a new thread and twice in the GUI thread. Thre return value calcualted in the new thread is not used.

Try replacing :

                Thread foregroundthread = new Thread(() => CheckOffice(OfficeIPAddress));
                foregroundthread.Start();

                //check if connection to remote server is available
                if (CheckOffice(OfficeIPAddress) == 1)
                {
                    DGV_OfficeList[4, DGV_OfficeList.CurrentCell.RowIndex].Value = "Connected";
                    //file.copy(sorucefilenamepath, destinationfilenamepath, true); //copy files...
                }
                else if (CheckOffice(OfficeIPAddress) == 0)
                {
                    DGV_OfficeList[4, DGV_OfficeList.CurrentCell.RowIndex].Value = "disconnected";
                }

with

        var task = Task.Run(() =>
            {
                var result = CheckOffice(OfficeIPAddress);

                this.BeginInvoke((Action)(() =>
                {
                    if (result == 1)
                    {
                        DGV_OfficeList[4, DGV_OfficeList.CurrentCell.RowIndex].Value = "Connected";
                        //file.copy(sorucefilenamepath, destinationfilenamepath, true); //copy files...
                    }
                    else if (result == 0)
                    {
                        DGV_OfficeList[4, DGV_OfficeList.CurrentCell.RowIndex].Value = "disconnected";
                    }
                }));
            }
        );

This uses a Task rather than an explicit Thread, which is better practice if you just want to launch asynchronous logic, and then uses BeginInvoke to apply the update to the GUI using the GUI thread as otherwise this will cause issues with the DataGridView control which is not thread-safe. BeginInvoke should be defined on your Winforms Window or Control, or you can look into Dispatcher.