XPlorerBar : Part 2 - Adding design-time support to the WPF explorer bar control

#region [       Copyright © 2008, Zona-Tools, all rights reserved.       ]
/*
 * 
    This source code is licensed under the Code Project Open License (CPOL).
    Check out http://www.codeproject.com/info/cpol10.aspx for further details.
 * 
*/
#endregion


#region [       Using namespaces       ]

using System;
using System.Windows;
using System.Windows.Controls;
using Microsoft.Windows.Design.Interaction;
using Microsoft.Windows.Design.Model;

#endregion


namespace ZonaTools.XPlorerBar.VisualStudio.Design
{
    /// <summary>
    /// Provides a context menu on any selected XPlorerSection object.
    /// </summary>
    internal class XPlorerSectionContextMenuProvider : PrimarySelectionContextMenuProvider
    {
        #region [       Constants       ]

        //Name of the parent's property which enables the nested items retrieval.
        const string parentChildrenRetrievalProperty = "Items";

        #endregion


        #region [       Fields       ]

        //'Expand/Collapse' menu item
        private MenuAction _expandCollapseMenuAction = new MenuAction("Expand");

        //'Manage section' sub-menu items
        private MenuAction _moveUpMenuAction = new MenuAction("Move up");
        private MenuAction _moveDownMenuAction = new MenuAction("Move Down");
        private MenuAction _IsPrimaryMenuAction = new MenuAction("IsPrimary");

        //'Manage items' sub-menu item
        private MenuAction _addXPlorerItemMenuAction = new MenuAction("Add an XPlorerItem");

        #endregion


        #region [       Constructor       ]

        //===========================================================================
        /// <summary>
        /// Default constructor.
        /// </summary>
        //===========================================================================
        public XPlorerSectionContextMenuProvider()
        {
            #region 'Expand/Collapse' menu

            //Adds handler on the 'Execute' event
            _expandCollapseMenuAction.Execute += 
                new EventHandler<MenuActionEventArgs>(_expandCollapseMenuAction_Execute);

            //Adds the menu to the context menu provider
            this.Items.Add(_expandCollapseMenuAction);

            #endregion

            #region 'Manage section' menu

            //Creates the 'Manage section' menu which holds the MenuAction items
            MenuGroup sectionFlyoutGroup =
                new MenuGroup("SectionGroup", "Manage section");
            sectionFlyoutGroup.HasDropDown = true;

            //Adds the MenuAction which moves the selected XPlorerSection up
            sectionFlyoutGroup.Items.Add(_moveUpMenuAction);
            _moveUpMenuAction.Execute += 
                new EventHandler<MenuActionEventArgs>(_moveUpMenuAction_Execute);

            //Adds the MenuAction which moves the selected XPlorerSection down
            sectionFlyoutGroup.Items.Add(_moveDownMenuAction);
            _moveDownMenuAction.Execute += 
                new EventHandler<MenuActionEventArgs>(_moveDownMenuAction_Execute);

            //Adds the MenuAction which sets the section as 'Primary'
            sectionFlyoutGroup.Items.Add(_IsPrimaryMenuAction);
            _IsPrimaryMenuAction.Execute += 
                new EventHandler<MenuActionEventArgs>(_IsPrimaryMenuAction_Execute);

            //Adds the menu to the ContextMenu provider
            this.Items.Add(sectionFlyoutGroup);

            #endregion

            #region 'Manage items' menu

            //Creates the 'Manage items' menu which holds the MenuAction items
            MenuGroup itemsFlyoutGroup =
                new MenuGroup("ItemsGroup", "Manage items");
            itemsFlyoutGroup.HasDropDown = true;

            //Adds the MenuAction which adds a new XPlorerItem to the XPlorerBar
            itemsFlyoutGroup.Items.Add(_addXPlorerItemMenuAction);
            _addXPlorerItemMenuAction.Execute += 
                new EventHandler<MenuActionEventArgs>(_addXPlorerItemMenuAction_Execute);

            //Adds the menu to the ContextMenu provider
            this.Items.Add(itemsFlyoutGroup);
            
            #endregion

            //Handles the event raised when the menu is about to be shown
            UpdateItemStatus += 
                new EventHandler<MenuActionEventArgs>(XPlorerSectionContextMenuProvider_UpdateItemStatus);
        }

        #endregion


        #region [       Updates the context menu       ]

        //===========================================================================
        /// <summary>
        /// Updates the context menu when it is about to be shown.
        /// </summary>
        /// <param name="sender">The object where the event handler is 
        /// attached.</param>
        /// <param name="e">The event data.</param>
        //===========================================================================
        private void XPlorerSectionContextMenuProvider_UpdateItemStatus(object sender, MenuActionEventArgs e)
        {
            //Gets a ModelItem which represents the selected control
            ModelItem selectedControl = e.Selection.PrimarySelection;

            #region 'Expand/Collapse' menu

            //Gets the value of the selected XPlorerSection 'IsExpanded' property
            ModelProperty isExpandedProperty =
                selectedControl.Properties[XPlorerSection.IsExpandedProperty];
            bool isExpanded = (bool)isExpandedProperty.ComputedValue;

            //Updates the menu item text according to the section status
            _expandCollapseMenuAction.DisplayName = (isExpanded ? "Collapse" : "Expand");

            #endregion

            #region 'Manage section' menu

            //Enables the 'Move up' item if the selected control is not the first section
            _moveUpMenuAction.Enabled =
                !ModelItemCollectionHelper.IsItFirstSection(selectedControl, parentChildrenRetrievalProperty);

            //Enables the 'Move down' item if the selected control is not the last section
            _moveDownMenuAction.Enabled =
                !ModelItemCollectionHelper.IsItLastSection(selectedControl, parentChildrenRetrievalProperty);

            //Enables and unchecks the 'IsPrimary' MenuAction item
            _IsPrimaryMenuAction.Enabled = true;
            _IsPrimaryMenuAction.Checkable = true;
            _IsPrimaryMenuAction.Checked = false;

            //Gets the value of the selected XPlorerSection 'IsPrimary' property
            ModelProperty isPrimaryProperty =
                selectedControl.Properties[XPlorerSection.IsPrimaryProperty];
            bool isPrimary = (bool)isPrimaryProperty.ComputedValue;

            //Updates the 'IsPrimary' MenuAction status
            _IsPrimaryMenuAction.Checked = isPrimary;

            #endregion
        }

        #endregion


        #region [       Expands or collapses the selected XPlorerSection       ]

        //===========================================================================
        /// <summary>
        /// Updates the 'IsExpanded' property of the selected XPlorerSection 
        /// according to the section status.
        /// </summary>
        /// <param name="sender">The object where the event handler is 
        /// attached.</param>
        /// <param name="e">The event data.</param>
        //===========================================================================
        private void _expandCollapseMenuAction_Execute(object sender, MenuActionEventArgs e)
        {
            //Gets a ModelItem which represents the selected control
            ModelItem selectedControl = e.Selection.PrimarySelection;

            //Gets the value of the selected XPlorerSection 'IsExpanded' property
            ModelProperty isExpandedProperty =
               selectedControl.Properties[XPlorerSection.IsExpandedProperty];
            bool isExpanded = (bool)isExpandedProperty.ComputedValue;

            //Updates the selected XPlorerSection 'IsExpanded' property
            isExpandedProperty.SetValue(!isExpanded);
        }

        #endregion


        #region [       Moves up and down the selected XPlorerSection       ]

        //===========================================================================
        /// <summary>
        /// Moves the selected XPlorerSection up in its parent container.
        /// </summary>
        /// <param name="sender">The object where the event handler is 
        /// attached.</param>
        /// <param name="e">The event data.</param>
        //===========================================================================
        private void _moveUpMenuAction_Execute(object sender, MenuActionEventArgs e)
        {
            //Gets a ModelItem which represents the selected control
            ModelItem selectedControl = e.Selection.PrimarySelection;

            //Moves the selected control up in its parent container
            ModelItemCollectionHelper.MoveItem(selectedControl, true, parentChildrenRetrievalProperty);
        }


        //===========================================================================
        /// <summary>
        /// Moves the selected XPlorerSection down in its parent container.
        /// </summary>
        /// <param name="sender">The object where the event handler is 
        /// attached.</param>
        /// <param name="e">The event data.</param>
        //===========================================================================
        private void _moveDownMenuAction_Execute(object sender, MenuActionEventArgs e)
        {
            //Gets a ModelItem which represents the selected control
            ModelItem selectedControl = e.Selection.PrimarySelection;

            //Moves the selected control down in its parent container
            ModelItemCollectionHelper.MoveItem(selectedControl, false, parentChildrenRetrievalProperty);
        }

        #endregion


        #region [       Adds a new XPlorerItem       ]

        //===========================================================================
        /// <summary>
        /// Adds a new XPlorerItem to the selected XPlorerSection.
        /// </summary>
        /// <param name="sender">The object where the event handler is 
        /// attached.</param>
        /// <param name="e">The event data.</param>
        //===========================================================================
        private void _addXPlorerItemMenuAction_Execute(object sender, MenuActionEventArgs e)
        {
            //Gets a ModelItem which represents the selected control
            ModelItem selectedControl = e.Selection.PrimarySelection;
            //and makes sure it is valid
            if (selectedControl == null)
                return;

            //Gets the selected XPlorerSection content
            ModelItem sectionContent = selectedControl.Properties["Content"].Value;

            //Makes sure the content of the selected XPlorerSection derived from Panel class
            if ((sectionContent == null) ||
                !sectionContent.ItemType.IsSubclassOf(typeof(Panel)))
            {
                MessageBox.Show("This operation requires a Panel element in XPlorerSection.Content",
                    "Warning message", MessageBoxButton.OK, MessageBoxImage.Warning);
                return;
            }

            //Opens edit mode
            using (ModelEditingScope batchedChange =
                selectedControl.BeginEdit("Adds a new XPlorerItem"))
            {
                //Creates a new XPlorerItem
                ModelItem newItem = ModelFactory.CreateItem(e.Context, typeof(XPlorerItem),
                    CreateOptions.InitializeDefaults, new Object[0]);
                //and adds it to the XPlorerSection.Content Panel children
                sectionContent.Properties["Children"].Collection.Add(newItem);

                //Commits all changes made in edit mode
                batchedChange.Complete();
            }
        }

        #endregion


        #region [       Sets the selected XPlorerSection 'IsPrimary' property       ]

        //===========================================================================
        /// <summary>
        /// Updates the 'IsPrimary' property of the selected XPlorerSection 
        /// according to the user choice.
        /// </summary>
        /// <param name="sender">The object where the event handler is 
        /// attached.</param>
        /// <param name="e">The event data.</param>
        //===========================================================================
        private void _IsPrimaryMenuAction_Execute(object sender, MenuActionEventArgs e)
        {
            //Gets a ModelItem which represents the selected control
            ModelItem selectedControl = e.Selection.PrimarySelection;

            //Gets the value of the selected XPlorerSection 'IsPrimary' property
            ModelProperty isPrimaryProperty =
                selectedControl.Properties[XPlorerSection.IsPrimaryProperty];

            //Gets the value of the item selected by the user
            bool selectedIsPrimary = ((MenuAction)sender).Checked;

            //Updates the selected XPlorerSection 'IsPrimary' property
            isPrimaryProperty.SetValue(selectedIsPrimary);
        }

        #endregion
    }
}