249 lines
9.2 KiB
C#
249 lines
9.2 KiB
C#
using System.Collections;
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using System.Windows.Controls.Primitives;
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using System.Windows.Data;
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using System.Windows.Input;
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namespace Melskin.Controls
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{
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/// <summary>
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/// AutoComplete 控件提供了一个文本框，用户可以在其中输入文本，并从一个下拉列表中选择建议项。该控件适用于需要快速完成或查找功能的场景。
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/// </summary>
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/// <remarks>
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/// 通过设置 ItemsSource 属性，可以为 AutoComplete 控件提供数据源，用于填充建议列表。当用户在文本框中输入时，会根据输入的内容显示匹配的建议项。
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/// </remarks>
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[TemplatePart(Name = "PART_TextBox", Type = typeof(TextBox))]
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[TemplatePart(Name = "PART_Popup", Type = typeof(Popup))]
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[TemplatePart(Name = "PART_ListBox", Type = typeof(ListBox))]
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public class AutoComplete : Control
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{
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private TextBox? textBox;
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private Popup? popup;
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private ListBox? listBox;
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private bool isSelectionChanging = false;
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private const int filterDelay = 200;
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private CancellationTokenSource? cts;
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#region Dependency Properties
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/// <summary>
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/// 用于设置或获取 AutoComplete 控件的数据源。该属性接受实现了 IEnumerable 接口的任何集合，这些数据将作为建议项显示给用户。
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/// </summary>
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public static readonly DependencyProperty ItemsSourceProperty =
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DependencyProperty.Register(nameof(ItemsSource), typeof(IEnumerable), typeof(AutoComplete), new PropertyMetadata(null, OnItemsSourceChanged));
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/// <summary>
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/// 用于设置或获取 AutoComplete 控件的数据源。该属性接受实现了 IEnumerable 接口的任何集合，这些数据将作为建议项显示给用户。
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/// </summary>
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public IEnumerable ItemsSource
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{
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get => (IEnumerable)GetValue(ItemsSourceProperty);
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set => SetValue(ItemsSourceProperty, value);
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}
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/// <summary>
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/// 用于设置或获取 AutoComplete 控件中文本框显示的文本。此属性支持双向数据绑定，允许在控件与数据源之间同步文本内容。
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/// </summary>
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public static readonly DependencyProperty TextProperty =
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DependencyProperty.Register(nameof(Text), typeof(string), typeof(AutoComplete), new FrameworkPropertyMetadata(string.Empty, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, OnTextChanged));
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/// <summary>
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/// 用于获取或设置 AutoComplete 控件中显示的文本。此属性支持双向数据绑定，允许用户输入的文本与外部数据源之间进行同步。
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/// </summary>
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public string Text
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{
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get => (string)GetValue(TextProperty);
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set => SetValue(TextProperty, value);
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}
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/// <summary>
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/// 用于设置或获取 AutoComplete 控件中当前选中的项。该属性支持双向数据绑定，可以用来反映用户从建议列表中选择的项目。
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/// </summary>
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public static readonly DependencyProperty SelectedItemProperty =
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DependencyProperty.Register(nameof(SelectedItem), typeof(object), typeof(AutoComplete), new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
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/// <summary>
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/// 获取或设置当前在 AutoComplete 控件中选中的项。此属性支持双向数据绑定，允许用户选择的项能够被外部逻辑访问和修改。
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/// </summary>
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public object? SelectedItem
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{
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get => GetValue(SelectedItemProperty);
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set => SetValue(SelectedItemProperty, value);
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}
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/// <summary>
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/// 用于设置或获取 AutoComplete 控件的下拉列表是否展开的状态。该属性为布尔值，当设置为 true 时，表示下拉列表处于打开状态；反之则关闭。
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/// </summary>
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public static readonly DependencyProperty IsDropDownOpenProperty =
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DependencyProperty.Register(nameof(IsDropDownOpen), typeof(bool), typeof(AutoComplete), new PropertyMetadata(false));
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/// <summary>
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///
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/// </summary>
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public bool IsDropDownOpen
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{
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get => (bool)GetValue(IsDropDownOpenProperty);
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set => SetValue(IsDropDownOpenProperty, value);
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}
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/// <summary>
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///
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/// </summary>
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public static readonly DependencyProperty PlaceholderTextProperty =
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DependencyProperty.Register(nameof(PlaceholderText), typeof(string), typeof(AutoComplete), new PropertyMetadata(string.Empty));
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/// <summary>
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///
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/// </summary>
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public string PlaceholderText
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{
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get => (string)GetValue(PlaceholderTextProperty);
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set => SetValue(PlaceholderTextProperty, value);
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}
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#endregion
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static AutoComplete()
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{
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DefaultStyleKeyProperty.OverrideMetadata(typeof(AutoComplete), new FrameworkPropertyMetadata(typeof(AutoComplete)));
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}
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/// <inheritdoc />
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public override void OnApplyTemplate()
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{
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base.OnApplyTemplate();
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if (textBox != null)
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{
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textBox.TextChanged -= OnTextBoxTextChanged;
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textBox.PreviewKeyDown -= OnTextBoxPreviewKeyDown;
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}
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if (listBox != null)
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{
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listBox.SelectionChanged -= OnListBoxSelectionChanged;
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}
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textBox = GetTemplateChild("PART_TextBox") as TextBox;
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popup = GetTemplateChild("PART_Popup") as Popup;
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listBox = GetTemplateChild("PART_ListBox") as ListBox;
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if (textBox != null)
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{
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textBox.TextChanged += OnTextBoxTextChanged;
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textBox.PreviewKeyDown += OnTextBoxPreviewKeyDown;
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}
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if (listBox != null)
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{
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listBox.SelectionChanged += OnListBoxSelectionChanged;
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}
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}
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private static void OnItemsSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
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{
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var control = (AutoComplete)d;
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if (control.listBox != null)
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{
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control.listBox.ItemsSource = e.NewValue as IEnumerable;
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}
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}
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private static async void OnTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
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{
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var control = (AutoComplete)d;
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if (control.isSelectionChanging) return;
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if (control.textBox != null && control.textBox.Text != (string)e.NewValue)
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{
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control.textBox.Text = (string)e.NewValue;
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}
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control.cts?.Cancel();
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control.cts = new CancellationTokenSource();
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try
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{
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await Task.Delay(filterDelay, control.cts.Token).ConfigureAwait(true);
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control.FilterItemsSource();
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}
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catch (TaskCanceledException)
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{
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// Ignore cancellation
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}
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}
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private void OnTextBoxTextChanged(object sender, TextChangedEventArgs e)
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{
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if (isSelectionChanging) return;
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// 同步Text属性
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if (textBox != null && Text != textBox.Text)
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{
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Text = textBox.Text;
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}
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// 清空我们自己控件的选中项
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SelectedItem = null;
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// 同时清空ListBox内部的选中项
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if (listBox is { SelectedItem: not null })
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{
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listBox.SelectedItem = null;
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}
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}
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private void OnTextBoxPreviewKeyDown(object sender, KeyEventArgs e)
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{
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if (e.Key == Key.Down && listBox is { Items.Count: > 0 })
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{
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listBox.Focus();
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listBox.SelectedIndex = 0;
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}
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else if (e.Key == Key.Escape)
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{
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IsDropDownOpen = false;
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}
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}
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private void OnListBoxSelectionChanged(object sender, SelectionChangedEventArgs e)
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{
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if (e.AddedItems.Count == 0 || listBox?.SelectedItem == null) return;
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isSelectionChanging = true;
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SelectedItem = listBox.SelectedItem;
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Text = SelectedItem?.ToString() ?? string.Empty;
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IsDropDownOpen = false;
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textBox?.Focus();
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textBox?.Select(textBox.Text.Length, 0);
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isSelectionChanging = false;
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}
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private void FilterItemsSource()
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{
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if (ItemsSource == null) return;
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var view = CollectionViewSource.GetDefaultView(ItemsSource);
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if (string.IsNullOrEmpty(Text))
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{
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view.Filter = null;
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}
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else
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{
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view.Filter = item => item.ToString()?.IndexOf(Text, StringComparison.OrdinalIgnoreCase) >= 0;
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}
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view.Refresh();
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// !string.IsNullOrEmpty(Tip) 的判断
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if (!string.IsNullOrEmpty(Text) && !view.IsEmpty && textBox is { IsKeyboardFocused: true })
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{
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IsDropDownOpen = true;
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}
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else
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{
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IsDropDownOpen = false;
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}
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}
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}
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} |