CODEWITHSUNDEEP
c#multithreadingbackgroundworker
Craig
Craig

Reputation: 18724

Winforms and Background Worker

I have a console app at the moment, which monitors a folder for files, and then based on rules and the file name, copies any new file to a location on the network.

I have a requirement to make the application more pretty, so decided to go with a simple WinForms single form application which displays status and 'last updated file' type information.

The console app was written in such a way that all Console display information went through a single method, which I called 'Notify', taking two parameters. A string to display the information I want the user to see, and an ErrorLevel Enum, which, if 'Normal' displayed in green text, if Warning, was yellow, and if error, was red. But the point is, all my code just did was use the 'Notify' method to output any text.

I want to change my console app into a normal class, run it as a background worker from the WinForms project, and have the Notify method in the thread send updates to the winforms app, safely. I think it can be done with events, but I am not sure what would be the best way to handle this. Could you propose a method to get this working?

There's the 'Invoke' way of doing things. Is it good? Something like:

this.BeginInvoke (new MethodInvoker(() => UpdateLabel(s));

It seems it would be basic, but I'd like to still make use of my Notify method, and have that send messages to the UI layer.

I also need the console app to send messages to the thread. For example, 'Stop', where I then run code that gracefully quits the thread... and also, 'Refresh', which does some logic within the thread.

Another option is to run the processing class as a service? And then have a UI that somehow connects to the system service and gets updates? I have never done anything like that, but the process is meant to run all the time...

At the moment, I have my code running, but no updated to the UI:

public partial class MainForm : Form
{
    BackgroundWorker _bw = new BackgroundWorker();
    public MainForm()
    {
        InitializeComponent();
    }

    private void MainForm_Load(object sender, EventArgs e)
    {

        _bw.DoWork += bw_DoWork;
        _bw.RunWorkerAsync();
    }

    private void bw_DoWork(object sender, DoWorkEventArgs e)
    {
        var bw = sender as BackgroundWorker;
        var monitor = new Monitor();
        monitor.RunMe();

    }
}

I think I just need to find a way to get my Notify method in my thread to send a message or something (An object that I create, with Message String and ErrorCode properties?) back to my UI, and process it safely on the UI.

And here is the code within the class (thread)...

public class Monitor
    {
        public void RunMe()
        {
            Notify("Checking for network connectivity...", Constants.ErrorLevel.Information);
            if (FileManagement.FolderExists(Constants.FolderToMonitor) == false)
            {
                Notify("Unable to monitor folder - Aborting.", Constants.ErrorLevel.Error);
                Console.ReadKey();
                return;
            }
            Notify("OK", Constants.ErrorLevel.Information);
....
}

Note: Readkey will be removed..

Upvotes: 2

Views: 837

Answers (1)

Brandon Dybala
Brandon Dybala

Reputation: 324

There may be a better approach, but if your Notify method needs to interact with the GUI, try using the ReportProgress event on the BackgroundWorker. You can pas an object as the state parameter, and probably just ignore the progress value.

Upvotes: 1

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