ShrlAlgoToolkit/WPFluent/Controls/ComboBoxEx/ComboBoxEx.cs

using System;
using System.Collections;
using System.Collections.Specialized;
using System.Windows.Controls;
using System.Windows.Data;


namespace WPFluent.Controls
{
    [TemplatePart(Name = FilterTextBox, Type = typeof(System.Windows.Controls.TextBox))]
    [TemplatePart(Name = "PART_EditableTextBox", Type = typeof(System.Windows.Controls.TextBox))]
    public class ComboBoxEx : ComboBox
    {
        private const string FilterTextBox = "PART_FilterTextBox";

        // Using a DependencyProperty as the backing store for FilterBoxPlaceholderText.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty FilterBoxPlaceholderTextProperty = DependencyProperty.Register(
            nameof(FilterBoxPlaceholderText),
            typeof(string),
            typeof(ComboBoxEx),
            new PropertyMetadata("输入关键字"));

        public static readonly DependencyProperty HeaderPlacementProperty = DependencyProperty.Register(
            nameof(HeaderPlacement),
            typeof(Dock),
            typeof(ComboBoxEx),
            new PropertyMetadata(Dock.Top));

        // Using a DependencyProperty as the backing store for Header.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty HeaderProperty = DependencyProperty.Register(
            nameof(Header),
            typeof(string),
            typeof(ComboBoxEx),
            new PropertyMetadata(null));

        public static readonly DependencyProperty PlaceholderTextProperty = DependencyProperty.Register(
            nameof(PlaceholderText),
            typeof(string),
            typeof(ComboBoxEx),
            new PropertyMetadata("请选择..."));
        public static readonly DependencyProperty ShowFilterBoxProperty = DependencyProperty.Register(
            nameof(ShowFilterBox),
            typeof(bool),
            typeof(ComboBoxEx),
            new PropertyMetadata(true));


        private System.Windows.Controls.TextBox filterTextBox;
        private ICollectionView view;

        static ComboBoxEx()
        {
            DefaultStyleKeyProperty.OverrideMetadata(
                typeof(ComboBoxEx),
                new FrameworkPropertyMetadata(typeof(ComboBoxEx)));
        }

        /// <summary>
        /// 过滤搜索
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void PART_FilterTextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            if (filterTextBox == null)
                return;

            if (view != null)
            {
                view.Filter += (o) =>
                {
                    if (o is string)
                    {
                        var value = o.ToString().ToLower();
                        return value.IndexOf(filterTextBox.Text.ToLower(), StringComparison.Ordinal) != -1;
                    }
                    else
                    {
                        var obj = GetPropertyValue(o, DisplayMemberPath);
                        //在xaml中写入Combobox时
                        if (obj is ComboBoxItem item)
                        {
                            obj = item.Content;
                        }
                        var value = Convert.ToString(obj).ToLower();
                        return value.IndexOf(filterTextBox.Text.ToLower(), StringComparison.Ordinal) != -1;
                    }
                };
            }
        }

        /// <summary>
        /// 获取view
        /// </summary>
        /// <param name="e"></param>
        /// <remarks>适用于在xaml中添加ComboBoxItem的情况</remarks>
        protected override void OnItemsChanged(NotifyCollectionChangedEventArgs e)
        {
            base.OnItemsChanged(e);
            view = CollectionViewSource.GetDefaultView(Items);
        }

        /// <summary>
        /// 获取view
        /// </summary>
        /// <param name="oldValue"></param>
        /// <param name="newValue"></param>
        /// <remarks>适用于绑定ItemsSource</remarks>
        protected override void OnItemsSourceChanged(IEnumerable oldValue, IEnumerable newValue)
        {
            base.OnItemsSourceChanged(oldValue, newValue);

            view = CollectionViewSource.GetDefaultView(ItemsSource);
        }

        /// <summary>
        /// 获取属性,若无法获取则返回源对象
        /// </summary>
        public static object GetPropertyValue(object obj, string path)
        {
            if (obj == null)
                return string.Empty;

            var result = obj;
            if (!string.IsNullOrEmpty(path))
            {
                var property = obj.GetType().GetProperty(path);
                if (property != null)
                {
                    try
                    {
                        result = property.GetValue(obj, null);
                        return result;
                    }
                    catch
                    {
                        try
                        {
                            var type = obj.GetType();
                            var mInfo = type.GetMethod($"get_{path}");
                            if (mInfo != null)
                            {
                                result = mInfo.Invoke(obj, null);
                                return result;
                            }
                        }
                        catch
                        {
                        }
                    }
                }
            }
            return result;
        }

        /// <summary>
        /// 应用样板
        /// </summary>
        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            if (filterTextBox != null)
            {
                filterTextBox.TextChanged -= PART_FilterTextBox_TextChanged;
            }

            filterTextBox = GetTemplateChild(FilterTextBox) as System.Windows.Controls.TextBox;
            if (filterTextBox != null)
            {
                filterTextBox.TextChanged += PART_FilterTextBox_TextChanged;
            }
        }

        [Category("自定义"), Bindable(true, BindingDirection.OneWay), Description("搜索框水印")]
        public string FilterBoxPlaceholderText
        {
            get { return (string)GetValue(FilterBoxPlaceholderTextProperty); }
            set { SetValue(FilterBoxPlaceholderTextProperty, value); }
        }

        [Category("自定义"), Bindable(true, BindingDirection.TwoWay), Description("标题")]
        public string Header
        {
            get { return (string)GetValue(HeaderProperty); }
            set { SetValue(HeaderProperty, value); }
        }

        //public bool PlaceholderEnable
        //{
        //	get { return (bool)GetValue(PlaceholderEnableProperty); }
        //	set { SetValue(PlaceholderEnableProperty, value); }
        //}

        //// Using a DependencyProperty as the backing store for PlaceholderEnable.  This enables animation, styling, binding, etc...
        //public static readonly DependencyProperty PlaceholderEnableProperty = DependencyProperty.Register(
        //	nameof(PlaceholderEnable),
        //	typeof(bool),
        //	typeof(ComboBoxEx),
        //	new PropertyMetadata(true)
        //);
        [Category("自定义"), Bindable(true, BindingDirection.OneWay), Description("标题位置")]
        public Dock HeaderPlacement
        {
            get { return (Dock)GetValue(HeaderPlacementProperty); }
            set { SetValue(HeaderPlacementProperty, value); }
        }

        /// <summary>
        ///
        /// </summary>
        /// <remarks>
        /// <para>特性含义：属性面板（支持分组，支持数据绑定，支持属性提示）</para>
        /// <para>[Category("自定义分组"),Bindable(true,BindingDirection.OneWay),Description("选择框水印")]</para>
        /// </remarks>
        [Category("自定义"), Bindable(true, BindingDirection.OneWay), Description("选择框水印")]
        public string PlaceholderText
        {
            get { return (string)GetValue(PlaceholderTextProperty); }
            set { SetValue(PlaceholderTextProperty, value); }
        }

        /// <summary>
        /// 获取或者设置下拉列表过滤文本框的显示与隐藏
        /// </summary>
        [Category("自定义"), Bindable(true, BindingDirection.OneWay), Description("过滤框")]
        public bool ShowFilterBox
        {
            get => (bool)GetValue(ShowFilterBoxProperty);
            set { SetValue(ShowFilterBoxProperty, value); }
        }
    }
}