MTP2.0_CSharp/Muchinfo.Common/Fx4.0/Xceed.Wpf.AvalonDock/Controls/DropDownButton.cs

/*************************************************************************************

   Extended WPF Toolkit

   Copyright (C) 2007-2013 Xceed Software Inc.

   This program is provided to you under the terms of the Microsoft Public
   License (Ms-PL) as published at http://wpftoolkit.codeplex.com/license 

   For more features, controls, and fast professional support,
   pick up the Plus Edition at http://xceed.com/wpf_toolkit

   Stay informed: follow @datagrid on Twitter or Like http://facebook.com/datagrids

  ***********************************************************************************/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Controls.Primitives;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Diagnostics;

namespace Xceed.Wpf.AvalonDock.Controls
{
    public class DropDownButton : ToggleButton
    {
        public DropDownButton()
        {
          this.Unloaded += new RoutedEventHandler(DropDownButton_Unloaded);
        }

        #region DropDownContextMenu

        /// <summary>
        /// DropDownContextMenu Dependency Property
        /// </summary>
        public static readonly DependencyProperty DropDownContextMenuProperty =
            DependencyProperty.Register("DropDownContextMenu", typeof(ContextMenu), typeof(DropDownButton),
                new FrameworkPropertyMetadata((ContextMenu)null,
                    new PropertyChangedCallback(OnDropDownContextMenuChanged)));

        /// <summary>
        /// Gets or sets the DropDownContextMenu property.  This dependency property 
        /// indicates drop down menu to show up when user click on an anchorable menu pin.
        /// </summary>
        public ContextMenu DropDownContextMenu
        {
            get { return (ContextMenu)GetValue(DropDownContextMenuProperty); }
            set { SetValue(DropDownContextMenuProperty, value); }
        }

        /// <summary>
        /// Handles changes to the DropDownContextMenu property.
        /// </summary>
        private static void OnDropDownContextMenuChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            ((DropDownButton)d).OnDropDownContextMenuChanged(e);
        }

        /// <summary>
        /// Provides derived classes an opportunity to handle changes to the DropDownContextMenu property.
        /// </summary>
        protected virtual void OnDropDownContextMenuChanged(DependencyPropertyChangedEventArgs e)
        {
            var oldContextMenu = e.OldValue as ContextMenu;
            if (oldContextMenu != null && IsChecked.GetValueOrDefault())
                oldContextMenu.Closed -= new RoutedEventHandler(OnContextMenuClosed);
        }

        #endregion

        #region DropDownContextMenuDataContext

        /// <summary>
        /// DropDownContextMenuDataContext Dependency Property
        /// </summary>
        public static readonly DependencyProperty DropDownContextMenuDataContextProperty =
            DependencyProperty.Register("DropDownContextMenuDataContext", typeof(object), typeof(DropDownButton),
                new FrameworkPropertyMetadata((object)null));

        /// <summary>
        /// Gets or sets the DropDownContextMenuDataContext property.  This dependency property 
        /// indicates data context to set for drop down context menu.
        /// </summary>
        public object DropDownContextMenuDataContext
        {
            get { return (object)GetValue(DropDownContextMenuDataContextProperty); }
            set { SetValue(DropDownContextMenuDataContextProperty, value); }
        }

        #endregion

        protected override void OnClick()
        {
            if (DropDownContextMenu != null)
            {
                //IsChecked = true;
                DropDownContextMenu.PlacementTarget = this;
                DropDownContextMenu.Placement = PlacementMode.Bottom;
                DropDownContextMenu.DataContext = DropDownContextMenuDataContext;
                DropDownContextMenu.Closed += new RoutedEventHandler(OnContextMenuClosed);
                DropDownContextMenu.IsOpen = true;
            }

            base.OnClick();
        }

        void OnContextMenuClosed(object sender, RoutedEventArgs e)
        {
            //Debug.Assert(IsChecked.GetValueOrDefault());
            var ctxMenu = sender as ContextMenu;
            ctxMenu.Closed -= new RoutedEventHandler(OnContextMenuClosed);
            IsChecked = false;
        }

        void DropDownButton_Unloaded(object sender, RoutedEventArgs e)
        {
          // When changing theme, Unloaded event is called, erasing the DropDownContextMenu.
          // Prevent this on theme changes.
          if( this.IsLoaded )
          {
            DropDownContextMenu = null;
          }
        }


    }
}