异步ComboBox过滤

Question

我对异步方法很陌生，并且为这种情况而挣扎(我用一个简单的例子说明了我的问题)：

假设我有一个ComboBox，哪些项与*BindableCollection NameList *绑定，哪些项是一些名称。

            <ComboBox
                x:Name="SubbranchComboBox"
                Margin="20 0 0 0"
                Width="100"
                Height="20"
                IsEnabled="True"
                IsEditable="True"
                IsTextSearchEnabled="False"
                InputScope="Xml"
                ItemsSource="{Binding NameList}" KeyUp="ComboBox_KeyUp">
            <ComboBox.ItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding}" />
                </DataTemplate>
            </ComboBox.ItemTemplate>
        </ComboBox>

ComboBox_KeyUp看起来如下所示：

        private void ComboBox_KeyUp(object sender, KeyEventArgs e)
    {
        var combobox = (ComboBox)sender;
        var ctb = combobox.Template.FindName("PART_EditableTextBox", combobox) as TextBox;
        if (ctb == null) return;
        if (Keyboard.Modifiers.HasFlag(ModifierKeys.Shift) || Keyboard.Modifiers.HasFlag(ModifierKeys.Control) || Keyboard.Modifiers.HasFlag(ModifierKeys.Alt))
            return;
        var caretPos = ctb.CaretIndex;
        var searchedText = combobox.Text.ToLower();
        combobox.SelectedIndex = -1;
        combobox.IsDropDownOpen = true;

        CollectionView itemsViewOriginal = (CollectionView)CollectionViewSource.GetDefaultView(combobox.Items);
        itemsViewOriginal.Filter = ((o) =>
        {
            if (String.IsNullOrEmpty(searchedText))
            {
                return true;
            }
            else
            {
                if (((string)o).ToLower().Contains(searchedText.ToLower()))
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
        });
        itemsViewOriginal.Refresh();
        ctb.CaretIndex = caretPos;
    }

并充当组合框中类型短语的搜索函数。问题是，我希望异步地进行过滤，但是每当我尝试这样做时，我都会得到一个错误：调用线程无法访问这个对象，因为另一个线程拥有它。

请给我一些建议，该怎么做。所有示例代码：

    public partial class MainWindow : Window
{
    public BindableCollection<String> NameList { get; set; }
    public MainWindow()
    {
        InitializeComponent();
        DataContext = this;
        NameList = new BindableCollection<String>
            {
                "Tony",
                "Jerry",
                "George",
                "Harry",
                "Snape",
                "Sirius",
                "Dan",
                "Michael",
                "Mike",
                "Sebastian",
                "Simon",
                "Johny"
            };
    }

    private void ComboBox_KeyUp(object sender, KeyEventArgs e)
    {
        var combobox = (ComboBox)sender;
        var ctb = combobox.Template.FindName("PART_EditableTextBox", combobox) as TextBox;
        if (ctb == null) return;
        if (Keyboard.Modifiers.HasFlag(ModifierKeys.Shift) || Keyboard.Modifiers.HasFlag(ModifierKeys.Control) || Keyboard.Modifiers.HasFlag(ModifierKeys.Alt))
            return;
        var caretPos = ctb.CaretIndex;
        var searchedText = combobox.Text.ToLower();
        combobox.SelectedIndex = -1;
        combobox.IsDropDownOpen = true;

        CollectionView itemsViewOriginal = (CollectionView)CollectionViewSource.GetDefaultView(combobox.Items);
        itemsViewOriginal.Filter = ((o) =>
        {
            if (String.IsNullOrEmpty(searchedText))
            {
                return true;
            }
            else
            {
                if (((string)o).ToLower().Contains(searchedText.ToLower()))
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
        });
        itemsViewOriginal.Refresh();
        ctb.CaretIndex = caretPos;
    }
}

Answer 1

问题是，我希望异步地进行过滤，但是每当我尝试这样做时，我就会得到一个错误:调用线程无法访问这个对象，因为另一个线程拥有它。

如果要从后台线程更新UI，则应在Application的dispatcher中运行代码

Application.Current.Dispatcher.Invoke(() => /* modify combobox here */);