XPlorerBar: A WPF Windows XP Style 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.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Xml;

#endregion


namespace ZonaTools.XPlorerBar
{
    /// <summary>
    /// Represents a control used to display grouped command items (as the
    /// task bar that was introduced in Windows XP's explorer).
    /// </summary>
    public class XPlorerBar : ItemsControl
    {
        #region [       Constants       ]

        /// <summary>
        /// Name of the XPlorerSection's properties category in the property grid
        /// of the control.
        /// </summary>
        internal const string CATEGORYNAME = "Zona-Tools Properties";

        #endregion


        #region [       Built-in themes declarations       ]

        /// <summary>
        /// Windows Vista Aero theme.
        /// </summary>
        public static Theme AeroNormalColorTheme = new Theme(
            Themes.Aero.ToString(),
            "/ZonaTools.XPlorerBar;component/Themes/Aero.NormalColor.xaml");
        /// <summary>
        /// Windows NT Classic theme.
        /// </summary>
        public static Theme ClassicTheme = new Theme(
            Themes.Classic.ToString(),
            "/ZonaTools.XPlorerBar;component/Themes/Classic.xaml");
        /// <summary>
        /// Windows XP Luna olive green theme.
        /// </summary>
        public static Theme LunaHomesteadTheme = new Theme(
            Themes.LunaOliveGreen.ToString(),
            "/ZonaTools.XPlorerBar;component/Themes/Luna.Homestead.xaml");
        /// <summary>
        /// Windows XP Luna silver theme.
        /// </summary>
        public static Theme LunaMetallicTheme = new Theme(
            Themes.LunaSilver.ToString(),
            "/ZonaTools.XPlorerBar;component/Themes/Luna.Metallic.xaml");
        /// <summary>
        /// Windows XP Luna blue theme.
        /// </summary>
        public static Theme LunaNormalColorTheme = new Theme(
            Themes.LunaBlue.ToString(),
            "/ZonaTools.XPlorerBar;component/Themes/Luna.NormalColor.xaml");
        /// <summary>
        /// Windows XP Royale theme.
        /// </summary>
        public static Theme RoyaleNormalColorTheme = new Theme(
            Themes.Royale.ToString(),
            "/ZonaTools.XPlorerBar;component/Themes/Royale.NormalColor.xaml");
        /// <summary>
        /// Windows XP Zune theme.
        /// </summary>
        public static Theme ZuneNormalColorTheme = new Theme(
            Themes.Zune.ToString(),
            "/ZonaTools.XPlorerBar;component/Themes/Zune.NormalColor.xaml");
        /// <summary>
        /// Microsoft Blend theme.
        /// </summary>
        public static Theme BlendTheme = new Theme(
            Themes.Blend.ToString(),
            "ZonaTools.XPlorerBar;component/Themes/BlendDictionary.xaml");

        #endregion


        #region [       Constructor       ]

        //===========================================================================
        /// <summary>
        /// Static constructor used to override the dependency properties (if
        /// needed) and define the default style for the control.
        /// </summary>
        //===========================================================================
        static XPlorerBar()
        {
            //Provides a new default style for the XPlorerBar element
            DefaultStyleKeyProperty.OverrideMetadata(typeof(XPlorerBar), 
                new FrameworkPropertyMetadata(typeof(XPlorerBar)));
        }

        //===========================================================================
        /// <summary>
        /// Default constructor.
        /// </summary>
        //===========================================================================
        public XPlorerBar()
        {
            //Adds an event handler on the 'Expanded' event of an XPlorerSection
            this.AddHandler(XPlorerSection.ExpandedEvent, 
                new RoutedEventHandler(this.OnExpanderHasExpanded));

            //Registers the built-in themes for the XPlorerBar class
            ThemeManager.RegisterTheme(AeroNormalColorTheme, typeof(XPlorerBar));
            ThemeManager.RegisterTheme(ClassicTheme, typeof(XPlorerBar));
            ThemeManager.RegisterTheme(LunaHomesteadTheme, typeof(XPlorerBar));
            ThemeManager.RegisterTheme(LunaMetallicTheme, typeof(XPlorerBar));
            ThemeManager.RegisterTheme(LunaNormalColorTheme, typeof(XPlorerBar));
            ThemeManager.RegisterTheme(RoyaleNormalColorTheme, typeof(XPlorerBar));
            ThemeManager.RegisterTheme(ZuneNormalColorTheme, typeof(XPlorerBar));
            ThemeManager.RegisterTheme(BlendTheme, typeof(XPlorerBar));
        }

        #endregion


        #region [       Dependency properties       ]

        #region AllowMultipleExpands property

        //===========================================================================
        /// <summary>
        /// Gets or sets a value indicating whether multiple XPlorerSection can be
        /// expanded at the same time. This is a dependency property.
        /// </summary>
        /// <remarks>
        /// The default value is <c>true</c>.
        /// </remarks>
        //===========================================================================
        [Category(CATEGORYNAME), Browsable(true)]
        public bool AllowMultipleExpands
        {
            get { return (bool)GetValue(AllowMultipleExpandsProperty); }
            set { SetValue(AllowMultipleExpandsProperty, value); }
        }

        /// <summary>
        /// Identifies the <see cref="AllowMultipleExpands"/> dependency property.
        /// </summary>
        public static readonly DependencyProperty AllowMultipleExpandsProperty =
            DependencyProperty.Register("AllowMultipleExpands",
            typeof(bool), typeof(XPlorerBar),
            new FrameworkPropertyMetadata(true, new PropertyChangedCallback(OnAllowMultipleExpandsChanged)));

        /// <summary>
        /// Invoked whenever the <c>AllowMultipleExpands</c> dependency property value
        /// has been updated.
        /// </summary>
        /// <param name="sender">The <c>DependencyObject</c> on which the property
        /// has changed value.</param>
        /// <param name="e">Event data that is issued by any event that tracks changes 
        /// to the effective value of this property. </param>
        private static void OnAllowMultipleExpandsChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            //Gets the XPlorerBar who sent the event
            XPlorerBar xpBar = (XPlorerBar)sender;
            //Gets the new value of the 'AllowMultipleExpands' DP
            bool newAllowMultipleExpands = (bool)e.NewValue;
            
            //If the new value is not 'Allow multiple expands'
            if (!newAllowMultipleExpands)
                //collapses every XPlorerSection except one
                xpBar.ManageSingleExpand(null);
        }

        #endregion

        #endregion


        #region [       Single/multiple expands management       ]

        //===========================================================================
        /// <summary>
        /// Invoked whenever the <c>XPlorerSection.IsExpanded</c> dependency property 
        /// value has been updated.
        /// </summary>
        /// <param name="sender">The object where the event handler is 
        /// attached.</param>
        /// <param name="args">The event data.</param>
        //===========================================================================
        private void OnExpanderHasExpanded(object sender, RoutedEventArgs args)
        {
            //Gets the XPlorerSection instance that has been expanded
            XPlorerSection exp = args.OriginalSource as XPlorerSection;

            //If multiple expands are not allowed, updates the 'IsExpanded' DP of
            //all the nested XPlorerSection instances
            if (!AllowMultipleExpands)
                ManageSingleExpand(exp);
        }


        //===========================================================================
        /// <summary>
        /// Updates the <c>IsExpanded</c> DP of all the nested XPlorerSection
        /// instances in order to have only one expanded XPlorerSection.
        /// </summary>
        /// <param name="xpSection">XPlorerSection instance that has been expanded.
        /// Null, if no XPlorerSection has been expanded.</param>
        /// <remarks>
        /// On intialization or when the <c>AllowMultipleExpands</c> DP has been
        /// updated, call this method with <c>null</c> as a parameter.
        /// </remarks>
        //===========================================================================
        private void ManageSingleExpand(XPlorerSection xpSection)
        {
            bool foundAnExpandedXPSection = false;

            //Loops the nested XPlorerSection
            for (int index = 0; index < this.Items.Count; index++)
            {
                //Gets the (index)th XPlorerSection
                XPlorerSection curSection = this.Items[index] as XPlorerSection;

                //Remark: curSection is null in binding mode => in binding mode,
                //the AllowMultipleExpands = False must not be active.
                if (curSection != null)
                {
                    //If the parameter is not null (i.e. xpSection is being expanded)
                    if (xpSection != null)
                    {
                        //All the other sections have to be collapsed
                        if (!curSection.Equals(xpSection))
                            curSection.IsExpanded = false;
                    }
                    else //i.e. Initialization or 'AllowMultipleExpands' DP is set to false
                    {
                        //if there is at least one expanded XPlorerSection
                        if (foundAnExpandedXPSection)
                            //Collapses the current XPlorerSection
                            curSection.IsExpanded = false;
                        else
                        {
                            //If the current XPlorerSection is expanded
                            if (curSection.IsExpanded)
                                //sets the 'foundAnExpandedXPSection' flag to true
                                foundAnExpandedXPSection = true;
                        }
                    }
                }
            }
        }

        #endregion


        #region [       Layout helpers       ]

        ////===========================================================================
        ///// <summary>
        ///// Determines if the specified item is (or is eligible to be) its own 
        ///// container.
        ///// </summary>
        ///// <param name="item">The item to check.</param>
        ///// <returns><c>true</c> if the item is (or is eligible to be) its own container; 
        ///// otherwise, <c>false.</c></returns>
        ////===========================================================================
        //protected override bool IsItemItsOwnContainerOverride(object item)
        //{
        //    return (item is XPlorerSection);
        //}


        ////===========================================================================
        ///// <summary>
        ///// Creates or identifies the element that is used to display the given item.
        ///// </summary>
        ///// <returns>The element that is used to display the given item.</returns>
        ////===========================================================================
        //protected override DependencyObject GetContainerForItemOverride()
        //{
        //    return new XPlorerSection();
        //}

        #endregion
    }
}