C＃BackgroundWorker streamreader每隔几秒钟重复一次

Question

So I am trying to build an SSH company for my own use that simplifies things for my project ( I am working on an ecommerce website and I have to reindex manually due to cron errors ) so this SSH tool is supposed to make things easier.

I want my program to give me a live result when I execute a command. I currently think that a timer could be the solution, sadly I haven't been successful. not only that but I've tried several things but for some reason the "ProgressChanged"seems to do nothing, atleast not when I'm trying something.

I've read a few threads This one for example , which explains what and how, but I am not able to do it for myself, so my question was if someone could help me achieve this.

 private void btnUitvoeren_Click(object sender, EventArgs e)
    {
        backgroundWorker.RunWorkerAsync();

        lblStatus.Text = "Process is bezig... een moment geduld aub";
        lblStatus.ForeColor = Color.Orange;
    }

    public void ReindexCommand()
    {
        var cmd = client.CreateCommand(txtBoxInput.Text);
        var result = cmd.Execute();
        this.Invoke(new Action(() =>
        {
            rTxtBoxOutput.Text += result;

            var reader = new StreamReader(cmd.ExtendedOutputStream);
            rTxtBoxOutput.Text += "\n" + reader.ReadToEnd();
        }
         ));
    }

    public void backgroundWorker_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
    {
        ReindexCommand();
    }

    private void backgroundWorker_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)
    {
                    // Gonna work on this        
    }

    private void backgroundWorker_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)
    {

        lblStatus.Text = "Process Compleet";
        lblStatus.ForeColor = Color.Green;
    }

Answer 1

I've made a small example for you how to use the background-worker correctly. Remark that all objets that are needed to do the background-stuff should be passed as an argument to the RunWorkerAsync -Method. You can not access your UI-Control in the DoWork-Method:

 private void InitializeBackgroundWorker()
    {
        backgroundWorker = new BackgroundWorker
        {
            WorkerReportsProgress = true
        };
        backgroundWorker.DoWork += backgroundWorker_DoWork;
        backgroundWorker.ProgressChanged += backgroundWorker_ProgressChanged;
        backgroundWorker.RunWorkerCompleted += backgroundWorker_RunWorkerCompleted;
    }
private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    // get your result-object and cast it to the desired type
    string myStringResult = (string)e.Result;

    // and here we are back in the UI-Thread
}

private void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
    // Now we are in the UI-Thread
    // get the passed progress-object and cast it to your desired type
    string myStringObject = (string)e.UserState;

    // do some UI-Stuff...
}

private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
    // get your argument 
    string input = (string)e.Argument;

    // do your async stuff
    // to call the progress-changed handler call
    ((BackgroundWorker)sender).ReportProgress(0, null /*Object to pass to the progress-changed method*/);


    // to pass an object to the completed-handler call
    e.Result = null; // null = your object

}

private void btnUitvoeren_Click(object sender, EventArgs e)
{
    backgroundWorker.RunWorkerAsync(txtBoxInput.Text);  // pass the input-string to the do-work method

    lblStatus.Text = "Process is bezig... een moment geduld aub";
}

If you use .net 4.5 or higher than you should take a look at async-await. If you want I can also make a small example for you how to use this