C#, WPF, Updating the gui without backgroundworkers

c#, wpf

Solution

You're still doing the long task in the main thread. You need to show the loading window in the main thread and do the long task in the background.

Using a BackgroundWorker is really the simplest solution for this:

BackgroundWorker bw;
LoadingWindow lw;

public Window1() {
    bw = new BackgroundWorker();
    lw = new LoadingWindow();

    bw.DoWork += (sender, args) => {
        // do your lengthy stuff here -- this will happen in a separate thread
        ...
    }

    bw.RunWorkerCompleted += (sender, args) => {
        if (args.Error != null)  // if an exception occurred during DoWork,
            MessageBox.Show(args.Error.ToString());  // do your error handling here

        // close your loading window here
        ...
    }

    // open and show your loading window here
    ...

    bw.RunWorkerAsync(); // starts the background worker
}

Problem

I have a program that takes 10-20 seconds to start. I need to show a window with a progress bar when the program starts up. I know BackgroundWorker's are the correct way to do this but I unfortunately don't have the time to rework the whole gui using threads right now. Here is some code I'm trying but it is not working. Can anyone help..? ``` using System; using System.Threading; using System.Windows; namespace WpfApplication1 { public partial class Window1 : Window { public Window1() { InitializeComponent(); Thread t = new Thread(ShowLoadingWindow); t.SetApartmentState(ApartmentState.STA); t.Priority = ThreadPriority.Highest; t.Start(); DoSomeLongTask(); keepLooping = false; } bool keepLooping = true; private void ShowLoadingWindow() { LoadingWindow lw = new LoadingWindow(); lw.Show(); while (keepLooping) { Thread.Sleep(1); } lw.Close(); } private void DoSomeLongTask() { for (int i = 0; i < 20000; i++) { GC.Collect(); } } } } ``` The loading window is just a bare window with a progress bar. Howcome this doesn't work?

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