通过键盘“提前键入”搜索选择WPF列表框中的项目

查看TextSearch类,特别是附加的TextSearch.TextPath属性:

<ListBox TextSearch.TextPath="FolderName" ... />

text search.TextPath属性启用文本搜索并指定如何从每个项目中提取搜索文本。在本例中,我假设每个文件夹对象都有一个名为“FolderName”的属性。

如果这不能实现你想要的所有功能,你可能需要实现你自己的搜索,因为TextSearch功能不是特别好用。为此:

1. 处理TextInput事件
2. 比较当前文本输入和以前文本输入的时间。如果靠得足够近,则追加到前缀字符串,否则将其设置为键入的单个字符。
3. 在所有项目中搜索给定前缀&如果找到,请设置SelectedItem。

我将使用附加属性将其构建为一个单独的类,类似于内置的TextSearch类。

我使用的是一个隐藏的文本框,当用户输入时它会短暂出现,几秒钟后重置并清除,这样在计时器过期后它就不会尝试匹配其内容。这个人会在列表框中键入 KeyUp 事件将填充文本框,因为 SearchText . 什么时候? 搜索文本 充满了,就会触发 MyFilteredItems() 在该文本和列表框之间执行匹配。然后,如果此人按Enter键,则所选内容将进入另一个文本框(未在XAML中列出,但在代码中以注释形式提供)并从中清除 lstPickList . 然后清除文本框并重置计时器。

XAML:

<TextBox Name="txtPicker" IsReadOnly="True" Foreground="LightGreen" FontFamily="Consolas" Text="{Binding SearchText, UpdateSourceTrigger=PropertyChanged}"></TextBox>

<ListBox Name="lstPickList" Grid.Row="1" ItemsSource="{Binding MyFilteredItems}" KeyUp="lstPickList_KeyUp"></ListBox>

然后这就是后面的相关代码:

public partial class MainWindow : Window, INotifyPropertyChanged
{
    private Timer t = new Timer();    
    public System.Windows.Threading.DispatcherTimer tCleanup =
         new System.Windows.Threading.DispatcherTimer();

    private string _searchText; 
    public string SearchText
    {
        get { return _searchText; }
        set
        {
            _searchText = value;

            OnPropertyChanged("SearchText");
            OnPropertyChanged("MyFilteredItems");
        }
    }

    public List<string> MyItems { get; set; }        

    public IEnumerable<string> MyFilteredItems
    {
        get
        {
            if (SearchText == null) return MyItems;

            return MyItems.Where(x => x.ToUpper().StartsWith(SearchText.ToUpper()));
        }            
    }


    public MainWindow()
    {
        InitializeComponent();

        MyItems = new List<string>() { "ABC", "DEF", "GHI" };                      
        this.DataContext = this;

        t.Interval = 1000;
        t.Elapsed += new ElapsedEventHandler(timerCounter);
        tCleanup.Interval = new TimeSpan(0,0,1);
        tCleanup.Tick += new EventHandler(cleanupCounter_Tick);        
        txtPicker.Visibility = Visibility.Collapsed;
        tCleanup.Start();
    }
    private static int counter = 0;
    protected void timerCounter(object sender, ElaspedEventArgs e)
    {
        counter++;   
    }

   protected void cleanupCounter_Tick(object sender, EventArgs e)
   {
        if (counter > 2 && txtPicker.Visibility == Visibility.Visible)
            txtPicker.Visibility = Visibility.Collapsed;   
   }

   private void lstPickList_KeyUp(object sender, KeyEventArgs e)
   {
       ListBox lst = (ListBox)sender;
       string strg = Convert.ToString(e.Key.ToString().Replace("D",""));
       if (counter < 2)
       {
           txtPicker.Visibility = Visibility.Visible;
           t.Start();
           if (strg == "Return")
           {
                txtPicker.Text += "{Enter}";
                SearchText += "{Enter}";
           }
           else
           {
               txtPicker.Text += strg;
               SearchText += strg;
           }
      }
      else
      {
          SearchText = strg;
          txtPicker.Text = strg;
          t.Stop();
          counter = 0;
          t.Start();
       }

       if (strg == "Return")
       {
           // This next line would be if you had a "selected items" ListBox to store the item
           // lstSelectedList.Items.Add(lstPickList.SelectedItem);
           lstPickList.Items.Remove(lstPickList.SelectedItem);
           t.Stop();
           txtPicker.Visibility = Visibility.Collapsed;
           counter = 0;
           txtPicker.Text = String.Empty;
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    void OnPropertyChanged(string name)
    {
        if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(name));
    }
}