PDFOffice_Windows_exe/PDF Office/CustomControl/CompositeControl/CustomComboControl.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace PDF_Office.CustomControl.CompositeControl
{
    //用法：
    // IsValueContent为ture时，使用ValueStr作为集合某项的值
    //IsValueContent为false时，使用Value作为集合某项的值
    //SetItemSource(List<ComboDataItem> items)更换集合List
    //默认：字体集合、IsValueContent为false、Value作为集合某项的值


    public class ComboDataItem
    {
        //字符串类型的值
        public string ValueStr { get; private set; }
        //数字类型的值
        public double Value { get; private set; }
        //下拉框显示的内容
        public string Content { get; private set; }
        //下拉框显示的内容+单位：限数字值的单位
        public string Unit { get; private set; }
        //数字类型
        public ComboDataItem(double value, string unitStr = "")
        {
            Content = value + unitStr;
            Value = value;
        }
        //字符串类型
        public ComboDataItem(string valueStr, string contentStr = "")
        {
            Content = contentStr;
            ValueStr = valueStr;
        }

    }
    /// <summary>
    /// CustomComboControl.xaml 的交互逻辑
    /// </summary>
    public partial class CustomComboControl : UserControl
    {
        public List<ComboDataItem> Items { get; private set; }
        public event RoutedEventHandler ValueChanged;

        public CustomComboControl()
        {
            InitializeComponent();
            Items = new List<ComboDataItem>();
            DefaultItems();
        }
        private void UserControl_Loaded(object sender, RoutedEventArgs e)
        {
            comBox.SelectionChanged -= comBox_SelectionChanged;
            comBox.SelectionChanged += comBox_SelectionChanged;
        }


        //更换集合
        public void SetItemSource(List<ComboDataItem> items)
        {
            SelectedIndex = - 1;//为了触发SelectedIndex
            Items = items;
            ItemSource = Items;
        }

        /// <summary>
        /// 默认集合（字体集合）
        /// </summary>
        private void DefaultItems()
        {
            Items.Clear();
            SelectedIndex = -1;

            var item = new ComboDataItem(3);
            Items.Add(item);
            item = new ComboDataItem(6);
            Items.Add(item);
            item = new ComboDataItem(9);
            Items.Add(item);
            item = new ComboDataItem(12);
            Items.Add(item);
            item = new ComboDataItem(15);
            Items.Add(item);
            item = new ComboDataItem(18);
            Items.Add(item);
            item = new ComboDataItem(21);
            Items.Add(item);
            item = new ComboDataItem(24);
            Items.Add(item);
            ItemSource = Items;
        }
 
        //下拉框选中项
        private void comBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var item = comBox.SelectedItem as ComboDataItem;
            if (item != null)
            {
                title.Text = item.Content;
                SelectedIndex = comBox.SelectedIndex;

                if (IsValueContent == false)
                {
                    Value = item.Value;
                    ValueChanged?.Invoke(Value, null);
                }
                    
                else
                {
                    ValueStr = item.ValueStr;
                    ValueChanged?.Invoke(ValueStr, null);
                }

            }


        }

        //在外部判断值是否存在于下拉框里
        public bool IsExistInComBox(object value)
        {
            if (value is double)
            {
                var item = Items.FirstOrDefault(temp => temp.Value == (double)Value);
                return (item == null ? false : true);
            }
            else if (value is string)
            {
                var item = Items.FirstOrDefault(temp => temp.ValueStr == (string)ValueStr);
                return (item == null ? false : true);
            }

            return false;
        }

        public double Value
        {
            get { return (double)GetValue(ValueProperty); }
            set { SetValue(ValueProperty, value); }
        }

        public string ValueStr
        {
            get { return (string)GetValue(ValueStrProperty); }
            set { SetValue(ValueStrProperty, value); }
        }

        //下拉框每项的值是否为字符串类型
        public bool IsValueContent
        {
            get { return (bool)GetValue(IsValueContentProperty); }
            set { SetValue(IsValueContentProperty, value); }
        }

        public List<ComboDataItem> ItemSource
        {
            get { return (List<ComboDataItem>)GetValue(ItemSourceProperty); }
            set { SetValue(ItemSourceProperty, value); }
        }

        public int SelectedIndex
        {
            get { return (int)GetValue(SelectedIndexProperty); }
            set { SetValue(SelectedIndexProperty, value); }
        }

        public ComboDataItem SelectedItems
        {
            get { return (ComboDataItem)GetValue(SelectedItemsProperty); }
            set { SetValue(SelectedItemsProperty, value); }
        }

        //外部需要下拉框都不选中时，true为不选中，false为正常选中
        public bool IsSelectedEmpty
        {
            get { return (bool)GetValue(IsSelectedEmptyProperty); }
            set { SetValue(IsSelectedEmptyProperty, value); }
        }

        public static readonly DependencyProperty IsSelectedEmptyProperty =
    DependencyProperty.Register("IsSelectedEmpty", typeof(bool), typeof(CustomComboControl), new PropertyMetadata(false, IsSelectedEmptyPropertyChanged));


        public static readonly DependencyProperty SelectedItemsProperty =
         DependencyProperty.Register("SelectedItems", typeof(ComboDataItem), typeof(CustomComboControl), new PropertyMetadata(null, SelectedItemsPropertyChanged));


        public static readonly DependencyProperty ValueProperty =
           DependencyProperty.Register("Value", typeof(double), typeof(CustomComboControl), new PropertyMetadata(1.0));

        public static readonly DependencyProperty ValueStrProperty =
         DependencyProperty.Register("ValueStr", typeof(string), typeof(CustomComboControl), new PropertyMetadata(""));

        public static readonly DependencyProperty ItemSourceProperty =
          DependencyProperty.Register("ItemSource", typeof(List<ComboDataItem>), typeof(CustomComboControl), new PropertyMetadata(null, SelectedItemSourcePropertyChanged));

        public static readonly DependencyProperty SelectedIndexProperty =
        DependencyProperty.Register("SelectedIndex", typeof(int), typeof(CustomComboControl), new PropertyMetadata(-1, SelectedIndexPropertyChanged));

        public static readonly DependencyProperty IsValueContentProperty =
          DependencyProperty.Register("IsValueContent", typeof(bool), typeof(CustomComboControl), new PropertyMetadata(false));

        //集合绑定下拉框 SelectedItems触发属性
        private static void IsSelectedEmptyPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var control = d as CustomComboControl;
            var isSelectedEmpty = (bool)e.NewValue;
            if(control != null)
            {
                //弃用：IsSelectedEmpty属性,可用SelectedItems == null来处理下拉框不选中的情况。

                //if(isSelectedEmpty)
                //{
                //    control.comBox.SelectedItem = null;
                //    control.SelectedIndex = -1;
                //    control.SelectedItems = null;
                //    control.title.Text = "";
                //}
            }
        }
        

        private static void SelectedItemsPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var control = d as CustomComboControl;
            var selectedItems = (ComboDataItem)e.NewValue;
            if (control != null /* && control.IsSelectedEmpty == false*/)
            {
                if(selectedItems != null)
                {
                    if (control.comBox.Items != null && control.comBox.Items.Count > 0)
                    {
                        if (control.IsValueContent)
                        {
                            control.ValueStr = selectedItems.ValueStr;
                        }
                        else
                        {
                            control.Value = selectedItems.Value;
                        }
                    }

                    if (control.comBox.Items == null || control.comBox.Items.Count == 0)
                    {
                        control.title.Text = selectedItems.Content;
                    }
                    else
                    {
                        int index = -1;
                        ComboDataItem temp;
                        if (control.IsValueContent)
                            temp = control.Items.FirstOrDefault(inlineItem => inlineItem.ValueStr == selectedItems.ValueStr);
                        else
                            temp = control.Items.FirstOrDefault(inlineItem => inlineItem.Value == selectedItems.Value);

                        if (temp != null)
                            index = control.Items.IndexOf(temp);


                        if (index >= 0)
                        {
                            if(control.SelectedIndex != index)
                            {
                                control.SelectedIndex = index;
                            }
                            //control.SelectedIndex = -1;
                            //control.SelectedIndex = index;
                        }
                        else
                            control.title.Text = selectedItems.Content;

                    }
                }

                else
                {
                    control.comBox.SelectedItem = null;
                    control.SelectedIndex = -1;
                    control.SelectedItems = null;
                    control.title.Text = "";
                }
              

            }
            
        }

        //集合绑定下拉框Itemsource触发属性
        private static void SelectedItemSourcePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var control = d as CustomComboControl;
            var itemsource = (List<ComboDataItem>)e.NewValue;
            if (control != null /*& control.IsSelectedEmpty == false*/)
            {
                control.SelectedIndex = -1;
                control.comBox.ItemsSource = itemsource;
                control.Items = itemsource;
                control.SelectedIndex = ((itemsource == null || itemsource.Count == 0) ? -1 : 0);
            }
        }

        //选中项触发属性
        private static void SelectedIndexPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var control = d as CustomComboControl;
            var selectedIndex = (int)e.NewValue;
            if (control != null /*&& control.IsSelectedEmpty == false*/)
            {
                if(control.comBox.Items != null && control.comBox.Items.Count > 0 && selectedIndex != -1)
                {
                    control.comBox.SelectedIndex = selectedIndex;
                    if (control.comBox.SelectedItem != null )
                        control.SelectedItems = (ComboDataItem)control.comBox.SelectedItem;
                    else
                        control.SelectedItems = null;
                }
                control.UpdateSelectedIndex();
            }
        }
        //选中项后，更新控件选中的显示内容
        public void UpdateSelectedIndex()
        {
            if(SelectedIndex < 0  || comBox.Items == null || comBox.Items.Count <= SelectedIndex)
            {
                title.Text = "";
            }
            else
            {
                if (IsSelectedEmpty == false)
                    title.Text = Items[SelectedIndex].Content;
            }
        }
    }
}