对话框表单上的WPF更新进度栏

Question

I have a ProgressBar on a form which I want to show as a dialog when the parent form is performing a long operation.

The ProgressWindow is simple:

The constructor takes in the max value and I have an increment method.

public ProgressWindow(int count)
{
    InitializeComponent();
    fileProgressBar.Maximum = count;
}

public void IncremntProgress()
{
    fileProgressBar.Value++;
}

On the parent I create an instance:

ProgressWindow progressWindow = new ProgressWindow(listOfFiles.Count);
progressWindow.Show();

I then run a large operation and I want to update the progressbar:

foreach (var file in listOfFiles)
{
    ....
    progressWindow.IncremntProgress();
}

progressWindow.Close();

This works but I'd like the form to be a dialog and the progress bar doesn't refresh correctly.

Is there a better way of updating a progress bar on a dialog window?

Answer 1

It's unclear what "doesn't refresh correctly" actually means here but you should run the "large operation" on a background thread and update any UI elements including the ProgressBar back on the UI thread:

Task.Run(() =>
{
    //...
    foreach (var file in listOfFiles)
    {
        //...
        progressWindow.Dispatcher.Invoke(new Action(()=> progressWindow.IncremntProgress()));
    }
}).ContinueWith(task => 
{
    progressWindow.Close();
}, System.Threading.CancellationToken.None, TaskContinuationOptions.None, TaskScheduler.FromCurrentSynchronizationContext());

The UI thread cannot both update the ProgressBar and run your operation/loop simultaneously.