107 lines
3.9 KiB
C#
107 lines
3.9 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Reflection;
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using System.Text;
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using System.Threading.Tasks;
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namespace Melskin.Controls
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{
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/// <summary>
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/// 搜索过滤的下拉框控件
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/// 自定义了ItemTemplate的时候，SearchableComboBox 设置 TextSearch.TextPath 附加属性,这个属性告诉 ComboBox：“虽然我的下拉列表长得很复杂（有颜色、有图标），但当你需要把我当成‘文本’处理（比如显示在输入框里、或者搜索时），请使用这个属性”
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/// </summary>
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public class SearchableComboBox : ComboBox
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{
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private TextBox _editableTextBox;
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private bool _isInternalOperation;
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static SearchableComboBox()
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{
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DefaultStyleKeyProperty.OverrideMetadata(typeof(SearchableComboBox), new FrameworkPropertyMetadata(typeof(SearchableComboBox)));
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}
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public SearchableComboBox()
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{
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IsEditable = true;
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IsTextSearchEnabled = false;
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StaysOpenOnEdit = true;
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}
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public override void OnApplyTemplate()
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{
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base.OnApplyTemplate();
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_editableTextBox = GetTemplateChild("PART_EditableTextBox") as TextBox;
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if (_editableTextBox != null)
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{
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_editableTextBox.TextChanged += OnEditableTextBoxTextChanged;
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// 点击时全选
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_editableTextBox.GotFocus += (s, e) => _editableTextBox.SelectAll();
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}
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}
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protected override void OnSelectionChanged(SelectionChangedEventArgs e)
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{
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if (_isInternalOperation) return;
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_isInternalOperation = true;
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base.OnSelectionChanged(e);
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// 重点 1：选中项改变后，必须彻底清空过滤器，否则下次打开下拉框只剩下一项
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this.Items.Filter = null;
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_isInternalOperation = false;
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}
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private void OnEditableTextBoxTextChanged(object sender, TextChangedEventArgs e)
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{
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if (_isInternalOperation) return;
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string searchText = _editableTextBox.Text;
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string selectedText = GetItemDisplayText(SelectedItem);
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// 重点 2：断开锁定逻辑
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// 如果文本框的内容和当前选中项的文本不一致，说明用户正在打字替换内容
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if (SelectedItem != null && searchText != selectedText)
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{
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_isInternalOperation = true;
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SelectedItem = null; // 必须将 SelectedItem 设为 null，否则 WPF 会强行还原文本
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_isInternalOperation = false;
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}
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// 重点 3：执行过滤
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this.Items.Filter = item =>
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{
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if (string.IsNullOrEmpty(searchText)) return true;
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string itemText = GetItemDisplayText(item);
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// 只要包含关键字就显示（忽略大小写）
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return itemText.IndexOf(searchText, StringComparison.OrdinalIgnoreCase) >= 0;
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};
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// 自动打开下拉框
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if (!IsDropDownOpen && _editableTextBox.IsFocused && !string.IsNullOrEmpty(searchText))
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{
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IsDropDownOpen = true;
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}
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}
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private string GetItemDisplayText(object item)
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{
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if (item == null) return string.Empty;
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if (item is ComboBoxItem cbi) return cbi.Content?.ToString() ?? string.Empty;
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// 兼容 DisplayMemberPath 或 TextSearch.TextPath
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string path = DisplayMemberPath;
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if (string.IsNullOrEmpty(path)) path = TextSearch.GetTextPath(this);
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if (!string.IsNullOrEmpty(path))
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{
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var prop = item.GetType().GetProperty(path);
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if (prop != null) return prop.GetValue(item)?.ToString() ?? string.Empty;
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}
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return item.ToString();
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}
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}
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}
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