SzmediTools/Szmedi.RvKits/AttachProps/BindingSelectItems.cs

using System;
using System.Collections;
using System.Linq;
using System.Windows;
using System.Windows.Controls.Primitives;

namespace Szmedi.RvKits.AttachProps
{
    class BindingSelectItems
    {
        public static IList GetSelectItemsAttach(DependencyObject obj)
        {
            return (IList)obj.GetValue(SelectItemsAttachProperty);
        }

        public static void SetSelectItemsAttach(DependencyObject obj, IList value)
        {
            obj.SetValue(SelectItemsAttachProperty, value);
        }

        // Using a DependencyProperty as the backing store for SelectItemsAttach.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty SelectItemsAttachProperty =
            DependencyProperty.RegisterAttached("SelectItemsAttach", typeof(IList), typeof(BindingSelectItems), new PropertyMetadata(null));



        public static bool GetSelectedChange(DependencyObject obj)
        {
            return (bool)obj.GetValue(SelectedChangeProperty);
        }

        public static void SetSelectedChange(DependencyObject obj, bool value)
        {
            obj.SetValue(SelectedChangeProperty, value);
        }

        // Using a DependencyProperty as the backing store for SelectedChange.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty SelectedChangeProperty =
            DependencyProperty.RegisterAttached("SelectedChange", typeof(bool), typeof(BindingSelectItems), new PropertyMetadata(false, SelectedChangedCallBack));

        private static void SelectedChangedCallBack(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (d is MultiSelector)
            {
                MultiSelector multiSelector = (MultiSelector)d;
                if ((bool)e.NewValue)
                {
                    multiSelector.SelectionChanged += MultiSelector_SelectionChanged;
                }
                else
                {
                    multiSelector.SelectionChanged -= MultiSelector_SelectionChanged;
                }
            }
            else
            {
                throw new InvalidOperationException();
            }
        }

        private static void MultiSelector_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)
        {
            MultiSelector multiSelector = (MultiSelector)sender;
            SetSelectItemsAttach(multiSelector, multiSelector.SelectedItems);
            System.Windows.Data.BindingExpression bind = multiSelector.GetBindingExpression(SelectItemsAttachProperty);
            bind?.UpdateSource();
        }

    }
}