基于WPF实现筛选下拉多选控件

WPF 实现筛选下拉多选控件

• 框架使用.NET4 至 .NET6；
• Visual Studio 2022;

创建 MultiSelectionSearchComboBox 继承 Control .

模板中创建两个 ListBox

• PART_Selector 用来显示所有 Item
• PART_SearchSelector 用于记录筛选到的 Item

Item 继承 ListBoxItem 并将样式模板修改为 CheckBox

解决 Popup 中 IME 不跟随 TextBox 问题

private static extern IntPtr SetFocus(IntPtr hWnd);

当 TextBox 中 Text 发生改变时通过循环 Item 中的 GetProperty 获取特定 DisplayMemberPath 属性，判断是否包含输入的 SearchText值，如果包含则添加PART_SearchSelector 中，当 SelectionChanged 事件更改时将修改 PART_Selector 中的内容。

实现代码

1）创建 MultiSelectionSearchComboBox.cs 代码如下:

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Interop;

namespace WPFDevelopers.Controls
{
    [TemplatePart(Name = "PART_TextBox", Type = typeof(TextBox))]
    [TemplatePart(Name = "PART_Popup", Type = typeof(Popup))]
    [TemplatePart(Name = "PART_Selector", Type = typeof(ListBox))]
    [TemplatePart(Name = "PART_SelectAll", Type = typeof(CheckBox))]
    [TemplatePart(Name = "PART_SearchSelector", Type = typeof(ListBox))]
    public class MultiSelectionSearchComboBox : Control
    {
        private const string TextBoxTemplateName = "PART_TextBox";
        private const string PopupTemplateName = "PART_Popup";
        private const string ListBoxTemplateName = "PART_Selector";
        private const string CheckBoxTemplateName = "PART_SelectAll";
        private const string ListBoxTemplateNameSearch = "PART_SearchSelector";

        public static readonly RoutedEvent ClosedEvent =
            EventManager.RegisterRoutedEvent("Closed",
                RoutingStrategy.Bubble,
                typeof(RoutedEventHandler),
                typeof(MultiSelectionSearchComboBox));

        public static readonly DependencyProperty DisplayMemberPathProperty =
           DependencyProperty.Register("DisplayMemberPath",
               typeof(string),
               typeof(MultiSelectionSearchComboBox),
               new PropertyMetadata(string.Empty));

        public static readonly DependencyProperty SelectedValuePathProperty =
           DependencyProperty.Register("SelectedValuePath",
               typeof(string),
               typeof(MultiSelectionSearchComboBox),
               new PropertyMetadata(string.Empty));

        public static readonly DependencyProperty TextProperty =
            DependencyProperty.Register("Text",
                typeof(string),
                typeof(MultiSelectionSearchComboBox),
                new PropertyMetadata(string.Empty));

        public static readonly DependencyProperty ItemsSourceProperty =
            DependencyProperty.Register("ItemsSource", typeof(IEnumerable), typeof(MultiSelectionSearchComboBox),
                new PropertyMetadata());

        public static readonly DependencyProperty ItemsSourceSearchProperty =
            DependencyProperty.Register("ItemsSourceSearch", typeof(IEnumerable), typeof(MultiSelectionSearchComboBox),
                new PropertyMetadata());

        public static readonly DependencyProperty SelectAllContentProperty =
            DependencyProperty.Register("SelectAllContent", typeof(object), typeof(MultiSelectionSearchComboBox),
                new PropertyMetadata("全选"));

        public static readonly DependencyProperty IsSelectAllActiveProperty =
            DependencyProperty.Register("IsSelectAllActive", typeof(bool), typeof(MultiSelectionSearchComboBox),
                new PropertyMetadata(false));

        public static readonly DependencyProperty DelimiterProperty =
            DependencyProperty.Register("Delimiter", typeof(string), typeof(MultiSelectionSearchComboBox),
                new PropertyMetadata(";"));

        public static readonly DependencyProperty IsDropDownOpenProperty =
            DependencyProperty.Register("IsDropDownOpen", typeof(bool), typeof(MultiSelectionSearchComboBox),
                new PropertyMetadata(false, OnIsDropDownOpenChanged));

        public static readonly DependencyProperty MaxDropDownHeightProperty =
            DependencyProperty.Register("MaxDropDownHeight", typeof(double), typeof(MultiSelectionSearchComboBox),
                new UIPropertyMetadata(SystemParameters.PrimaryScreenHeight / 3.0, OnMaxDropDownHeightChanged));

        public static readonly DependencyProperty SelectedItemsProperty =
            DependencyProperty.Register("SelectedItems", typeof(IList), typeof(MultiSelectionSearchComboBox),
                new FrameworkPropertyMetadata(null,
                    FrameworkPropertyMetadataOptions.BindsTwoWayByDefault | FrameworkPropertyMetadataOptions.Journal,
                    OnSelectedItemsChanged));

        public static readonly DependencyProperty SearchWatermarkProperty =
           DependencyProperty.Register("SearchWatermark",
               typeof(string),
               typeof(MultiSelectionSearchComboBox),
               new PropertyMetadata(string.Empty));

        private CheckBox _checkBox;
        private ListBox _listBox;
        private ListBox _listBoxSearch;
        private Popup _popup;
        private TextBox _textBox;
        private List