Question

Good evening,

I just started playing around with C# and I tried creating a GUI for a program that runs in command line. I have been able to get it running, but now I am stuck trying to implement a progress bar to it.

I have read other post but I am unable to find the exact issue or to understand how to apply the solution to my issue.

Here is my code (apologize if this is very messy):

private void MethodToProcess(Object sender, DoWorkEventArgs args)
    {
        // Set all the strings for passthrough
        String USMTPath_Work = USMTPath + USMTArch;
        String USMTPath_full = USMTPath_Work + @"\Scanstate.exe";
        String USMTFlags_Capture = @"/c /v:13 /o /l:scanstate.log /localonly /efs:copyraw";
        String Argument_full = SavePath + XML1 + XML2 + USMTFlags_Capture;

        // Test that USMT path is correct            
        if (USMTPath == null)
        {
            MessageBox.Show("Error: There is no USMT Path defined.");
            return;
        }

        // Test that Windows folder is correct when offline
        /* if (Windows_Path == null)
        {
            MessageBox.Show("Error: There is no Windows Path to capture.");
            return;
        } */

        // Runs the capture
        System.Diagnostics.Process Scanstate = new System.Diagnostics.Process();
        Scanstate.StartInfo.FileName = USMTPath_full;
        Scanstate.StartInfo.Arguments = Argument_full;
        Scanstate.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
        Scanstate.StartInfo.WorkingDirectory = USMTPath_Work;
        //Scanstate.StartInfo.UseShellExecute = false;
        Scanstate.StartInfo.CreateNoWindow = true;
        //Scanstate.StartInfo.RedirectStandardOutput = true;
        Scanstate.Start();
        Scanstate.WaitForExit();

        String Str_ExitCode = Scanstate.ExitCode.ToString();

        if (Scanstate.ExitCode == 1)
            MessageBox.Show("Error: Data has not been captured. Please check the log files for details.");
        if (Scanstate.ExitCode == 0)
            MessageBox.Show("Success: Data has been captured. For more information, check log files.");
        else
        {
            MessageBox.Show("Error: Unknown error has occurred. Please check the log files for details.");
            MessageBox.Show("Error Code: " + Str_ExitCode);
        }

        Scanstate.Close();

    }

Basically, I am trying to run the process scanstate.exe. Now, I am trying to run backgroundworker in order to be able to retrieve progress and pass it to the progressbar.

 private void btnCapture_Click(object sender, EventArgs e)
    {
        progressBar1.Minimum = 0;
        progressBar1.Maximum = 100;
        progressBar1.Step = 1;

        BackgroundWorker CaptureBG = new BackgroundWorker();
        CaptureBG.WorkerReportsProgress = true;
        CaptureBG.DoWork += new DoWorkEventHandler(MethodToProcess);
        CaptureBG.RunWorkerCompleted +=new RunWorkerCompletedEventHandler(CaptureBG_RunWorkerCompleted);
        CaptureBG.ProgressChanged += new ProgressChangedEventHandler(CaptureBG_ProgressChanged);
        CaptureBG.RunWorkerAsync();
    }

and

        private void CaptureBG_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs args)
    {
        progressBar1.Value = 100;
    }

    private void CaptureBG_ProgressChanged(object sender, ProgressChangedEventArgs args)
    {
        progressBar1.Value++;
    }

However I am either missunderstanding the use or I am missing something, since the process runs, but I don’t get any progress on the progressbar. It only fills once the process finish.

What am I doing wrong? In general, how would a process report progress if I don’t know exactly how long is going to take?

Thanks in advance

Answer 1

The BackgroundWorker is responsible for updating the progress as it gets further complete with its task.

There is no interaction between your process that you launch and your code that would provide progress of that process back to your code.

In order for this to work, two things have to happen:

1. You need to define a mechanism for your process to report progress to the BackgroundWorker.
2. The BackgroundWorker must update its own progress by calling the ReportProgress method so that the ProgressChanged event is fired.

The first step is the tricky one and depends on how scanstate.exe works. Does it do anything to give an indication of progress, such as write to the console? If so, you can redirect the console output and parse that output to determine or at least estimate progress.

UPDATE

Scanstate.exe provides the ability to write progress to a log, e.g.:

scanstate /i:migapp.xml /i:miguser.xml \\fileserver\migration\mystore /progress:prog.log /l:scanlog.log

You could use a FileWatcher in your BackgroundWorker to look for changes to the progress log and update progress accordingly.