threads confussion

Question

I have a WPF application, that makes textboxes dynamically, the thins is that if I put a very large number, it will freeze, so I think I need another thread, but how can Igetitbavck to the UI

    public ObservableCollection<SfTextBoxExt> TextBoxesCollection { get; set; }

        public int? Value { get; set; }

        public ICommand CreateCommand { get; set; }

        public ICommand CreateFoldersCommand { get; set; }

        public ICommand SaveCommand { get; set; }


        public MainWindowVM() {

            SaveCommand = new Command(SaveAction);

            TextBoxesCollection = new ObservableCollection<SfTextBoxExt>();

            CreateCommand = new Command(CreateAction);

            CreateFoldersCommand = new Command(CreateFolderAction);
        }

        private void SaveAction() {
            if (TextBoxesCollection.Count > 0) {
                SaveFileDialog fileDialog = new SaveFileDialog();
                if (fileDialog.ShowDialog() == true) {
                    File.WriteAllLines(fileDialog.FileName, (System.Collections.Generic.IEnumerable<string>)TextBoxesCollection);
                }
            }

        }

        private void CreateFolderAction() {

            var dirrName = "Assets";

            var workingDirectory = Environment.CurrentDirectory;

            // This will get the current PROJECT directory
            var projectDirectories = Directory.GetParent(workingDirectory).Parent.Parent.GetDirectories(dirrName)
                .ToList();

            var path = Path.GetFullPath(projectDirectories.First().FullName);

            foreach (var item in TextBoxesCollection) {
                if (!Directory.Exists($"{path}\\{item.Text}")) {
                    Directory.CreateDirectory($"{path}\\{item.Text}");
                }
            }
        }


        private void CreateAction() {

            for (int i = 0; i < Value; i++) {
                TextBoxesCollection.Add(new SfTextBoxExt() {
                    VerticalAlignment = VerticalAlignment.Center,
                    Margin = new Thickness(0, 10, 80, 0),
                    Watermark = "Folder name"
                });
            }
        }
    }
}

Answer 1

As far as I know, with the exception of certain scheduler objects, we cannot perform this operation in a non-UI thread. We can convert some values between UI threads and non-UI threads, not objects. (Quoted from here)

You can create elements in a background thread, but you can't do much to them. They belong to a background thread, and trying to attach them to a window created by the main thread will cause an error. Such as the question and the problem.

The solution is to avoid creating a large number of elements at once. If possible, you could try to split the work of creating 3000 elements into smaller blocks (for example, create 10 elements at a time) and use the lower priority Dispatcher.BeginInvoke to run these blocks one by one.

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