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Clipz - A Friendly Introduction to the Windows 7 Taskbar Features

, 17 Dec 2009
An overview of the Windows 7 taskbar features, and how to use then in your own applications.
Clipz.zip
Clipz
bin
Debug
Clipz.csproj.user
CopyIcon.ico
DeleteIcon.ico
Model
Native Methods
Properties
Settings.settings
Resources
Audio.png
Clipboard.png
NextIcon.ico
PreviousIcon.ico
Utility
Core
AppRestartRecovery
Dialogs
Common
TaskDialogs
Interop
AppRestartRecovery
Dialogs
NetworkList
PowerManagement
TaskDialogs
NetworkList
PowerManagement
Properties
PropertySystem
SafeHandles
Libraries
StructureMap.dll
Shell
Common
CommonFileDialogs
Controls
Design
ShellObjects.cd
ShellThumbnailClassDiagram.cd
DesktopWindowManager
ExplorerBrowser
ExplorerBrowserDiagram.cd
Interop
Common
Dialogs
ExplorerBrowser
KnownFolders
PropertySystem
StockIcons
Taskbar
KnownFolders
Properties
PropertySystem
StockIcons
Taskbar
//Copyright (c) Microsoft Corporation.  All rights reserved.

using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Security.Cryptography;
using Microsoft.WindowsAPICodePack.Shell.PropertySystem;
using MS.WindowsAPICodePack.Internal;

namespace Microsoft.WindowsAPICodePack.Shell
{
    /// <summary>
    /// The base class for all Shell objects in Shell Namespace.
    /// </summary>
    abstract public class ShellObject : IDisposable, IEquatable<ShellObject>
    {

        #region Public Static Methods

        /// <summary>
        /// Creates a ShellObject subclass given a parsing name.
        /// For file system items, this method will only accept absolute paths.
        /// </summary>
        /// <param name="parsingName">The parsing name of the object.</param>
        /// <returns>A newly constructed ShellObject object.</returns>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Globalization", "CA1304:SpecifyCultureInfo", MessageId = "System.String.ToLower")]
        public static ShellObject FromParsingName(string parsingName)
        {
            return ShellObjectFactory.Create(parsingName);
        }

        /// <summary>
        /// Indicates whether this feature is supported on the current platform.
        /// </summary>
        public static bool IsPlatformSupported
        {
            get
            {
                // We need Windows Vista onwards ...
                return CoreHelpers.RunningOnVista;
            }
        }

        #endregion

        #region Internal Fields

        /// <summary>
        /// Internal member to keep track of the native IShellItem2
        /// </summary>
        internal IShellItem2 nativeShellItem;

        #endregion

        #region Constructors
        
        internal ShellObject()
        {
        }

        internal ShellObject(IShellItem2 shellItem)
        {
            nativeShellItem = shellItem;
        }

        #endregion

        #region Protected Fields

        /// <summary>
        /// Parsing name for this Object e.g. c:\Windows\file.txt,
        /// or ::{Some Guid} 
        /// </summary>
        private string internalParsingName = null;

        /// <summary>
        /// A friendly name for this object that' suitable for display
        /// </summary>
        private string internalName = null;

        /// <summary>
        /// PID List (PIDL) for this object
        /// </summary>
        private IntPtr internalPIDL = IntPtr.Zero;

        #endregion

        #region Internal Properties

        /// <summary>
        /// Return the native ShellFolder object as newer IShellItem2
        /// </summary>
        /// <exception cref="System.Runtime.InteropServices.ExternalException">If the native object cannot be created.
        /// The ErrorCode member will contain the external error code.</exception>
        virtual internal IShellItem2 NativeShellItem2
        {
            get
            {
                if (nativeShellItem == null && ParsingName != null)
                {
                    Guid guid = new Guid(ShellIIDGuid.IShellItem2);
                    int retCode = ShellNativeMethods.SHCreateItemFromParsingName(ParsingName, IntPtr.Zero, ref guid, out nativeShellItem);

                    if (nativeShellItem == null || !CoreErrorHelper.Succeeded(retCode))
                    {
                        throw new ExternalException("Shell item could not be created.", Marshal.GetExceptionForHR(retCode));
                    }
                }
                return nativeShellItem;
            }
        }

        /// <summary>
        /// Return the native ShellFolder object
        /// </summary>
        virtual internal IShellItem NativeShellItem
        {
            get
            {
                return NativeShellItem2;
            }
        }

        /// <summary>
        /// Gets access to the native IPropertyStore (if one is already
        /// created for this item and still valid. This is usually done by the
        /// ShellPropertyWriter class. The reference will be set to null
        /// when the writer has been closed/commited).
        /// </summary>
        internal IPropertyStore NativePropertyStore
        {
            get;
            set;
        }

        #endregion

        #region Public Properties

        private ShellProperties properties = null;
        /// <summary>
        /// Gets an object that allows the manipulation of ShellProperties for this shell item.
        /// </summary>
        public ShellProperties Properties
        {
            get
            {
                if (properties == null)
                {
                    properties = new ShellProperties(this);
                }
                return properties;
            }
        }

        /// <summary>
        /// Gets the parsing name for this ShellItem.
        /// </summary>
        virtual public string ParsingName
        {
            get
            {
                if (internalParsingName == null && nativeShellItem != null)
                {
                    internalParsingName = ShellHelper.GetParsingName(nativeShellItem);
                }
                return internalParsingName;
            }
            protected set
            {
                this.internalParsingName = value;
            }
        }

        /// <summary>
        /// Gets the normal display for this ShellItem.
        /// </summary>
        virtual public string Name
        {
            get
            {
                if (internalName == null && NativeShellItem != null)
                {
                    IntPtr pszString = IntPtr.Zero;
                    HRESULT hr = NativeShellItem.GetDisplayName(ShellNativeMethods.SIGDN.SIGDN_NORMALDISPLAY, out pszString);
                    if (hr == HRESULT.S_OK && pszString != IntPtr.Zero)
                    {
                        internalName = Marshal.PtrToStringAuto(pszString);

                        // Free the string
                        Marshal.FreeCoTaskMem(pszString);

                    }
                }
                return internalName;
            }

            protected set
            {
                this.internalName = value;
            }
        }

        /// <summary>
        /// Gets the PID List (PIDL) for this ShellItem.
        /// </summary>
        virtual internal IntPtr PIDL
        {
            get
            {
                // Get teh PIDL for the ShellItem
                if (internalPIDL == IntPtr.Zero && NativeShellItem != null)
                    internalPIDL = ShellHelper.PidlFromShellItem(NativeShellItem);

                return internalPIDL;
            }
            set
            {
                this.internalPIDL = value;
            }
        }

        /// <summary>
        /// Overrides object.ToString()
        /// </summary>
        /// <returns>A string representation of the object.</returns>
        public override string ToString()
        {
            return this.Name;
        }

        /// <summary>
        /// Returns the display name of the ShellFolder object. DisplayNameType represents one of the 
        /// values that indicates how the name should look. 
        /// See <see cref="Microsoft.WindowsAPICodePack.Shell.DisplayNameType"/>for a list of possible values.
        /// </summary>
        /// <param name="displayNameType">A disaply name type.</param>
        /// <returns>A string.</returns>
        virtual public string GetDisplayName(DisplayNameType displayNameType)
        {
            string returnValue = null;

            HRESULT hr = HRESULT.S_OK;

            if (NativeShellItem2 != null)
                hr = NativeShellItem2.GetDisplayName((ShellNativeMethods.SIGDN)displayNameType, out returnValue);

            if (hr != HRESULT.S_OK)
                throw new COMException("Can't get the display name", (int)hr);

            return returnValue;
        }

        /// <summary>
        /// Gets a value that determines if this ShellObject is a link or shortcut.
        /// </summary>
        public bool IsLink
        {
            get
            {
                try
                {
                    ShellNativeMethods.SFGAO sfgao;
                    NativeShellItem.GetAttributes(ShellNativeMethods.SFGAO.SFGAO_LINK, out sfgao);
                    return (sfgao & ShellNativeMethods.SFGAO.SFGAO_LINK) != 0;
                }
                catch (FileNotFoundException)
                {
                    return false;
                }
                catch (NullReferenceException)
                {
                    // NativeShellItem is null
                    return false;
                }
            }
        }

        /// <summary>
        /// Gets a value that determines if this ShellObject is a file system object.
        /// </summary>
        public bool IsFileSystemObject
        {
            get
            {
                try
                {
                    ShellNativeMethods.SFGAO sfgao;
                    NativeShellItem.GetAttributes(ShellNativeMethods.SFGAO.SFGAO_FILESYSTEM, out sfgao);
                    return (sfgao & ShellNativeMethods.SFGAO.SFGAO_FILESYSTEM) != 0;
                }
                catch (FileNotFoundException)
                {
                    return false;
                }
                catch (NullReferenceException)
                {
                    // NativeShellItem is null
                    return false;
                }
            }
        }

        private ShellThumbnail thumbnail;
        /// <summary>
        /// Gets the thumbnail of the ShellObject.
        /// </summary>
        public ShellThumbnail Thumbnail
        {
            get
            {
                if (thumbnail == null)
                    thumbnail = new ShellThumbnail(this);

                return thumbnail;
            }
        }

        private ShellObject parentShellObject = null;
        /// <summary>
        /// Gets the parent ShellObject.
        /// Returns null if the object has no parent, i.e. if this object is the Desktop folder.
        /// </summary>
        public ShellObject Parent
        {
            get
            {
                if (parentShellObject == null && NativeShellItem2 != null)
                {
                    IShellItem parentShellItem = null;

                    HRESULT hr = NativeShellItem2.GetParent(out parentShellItem);

                    if (hr == HRESULT.S_OK && parentShellItem != null)
                        parentShellObject = ShellObjectFactory.Create(parentShellItem);
                    else if (hr == HRESULT.NO_OBJECT)
                    {
                        // Should return null if the parent is desktop
                        return null;
                    }
                    else
                    {
                        throw Marshal.GetExceptionForHR((int)hr);
                    }
                }

                return parentShellObject;
            }
        }


        #endregion

        #region IDisposable Members

        /// <summary>
        /// Release the native and managed objects
        /// </summary>
        /// <param name="disposing">Indicates that this is being called from Dispose(), rather than the finalizer.</param>
        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
            {
                internalName = null;
                internalParsingName = null;
                properties = null;
                thumbnail = null;
                parentShellObject = null;
            }

            if (internalPIDL != IntPtr.Zero)
            {
                ShellNativeMethods.ILFree(internalPIDL);
                internalPIDL = IntPtr.Zero;
            }

            if (nativeShellItem != null)
            {
                Marshal.ReleaseComObject(nativeShellItem);
                nativeShellItem = null;
            }

            if (NativePropertyStore != null)
            {
                Marshal.ReleaseComObject(NativePropertyStore);
                NativePropertyStore = null;
            }

        }

        /// <summary>
        /// Release the native objects.
        /// </summary>
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        /// <summary>
        /// Implement the finalizer.
        /// </summary>
        ~ShellObject()
        {
            Dispose(false);
        }

        #endregion

        #region equality and hashing

        /// <summary>
        /// Returns the hash code of the object.
        /// </summary>
        /// <returns></returns>
        public override int GetHashCode( )
        {
            if( !hashValue.HasValue )
            {
                uint size = ShellNativeMethods.ILGetSize( PIDL );
                if( size != 0 )
                {
                    byte[ ] pidlData = new byte[ size ];
                    Marshal.Copy( PIDL, pidlData, 0, (int)size );
                    byte[ ] hashData = ShellObject.hashProvider.ComputeHash( pidlData );
                    hashValue = BitConverter.ToInt32( hashData, 0 );
                }
                else
                {
                    hashValue = 0;
                }
                    
            }
            return hashValue.Value;
        }
        private static MD5CryptoServiceProvider hashProvider = new MD5CryptoServiceProvider( );
        private int? hashValue;

        /// <summary>
        /// Determines if two ShellObjects are identical.
        /// </summary>
        /// <param name="other">The ShellObject to comare this one to.</param>
        /// <returns>True if the ShellObjects are equal, false otherwise.</returns>
        public bool Equals(ShellObject other)
        {
            bool areEqual = false;

            if ((object)other != null)
            {
                IShellItem ifirst = this.NativeShellItem;
                IShellItem isecond = other.NativeShellItem;
                if (((ifirst != null) && (isecond != null)))
                {
                    int result = 0;
                    HRESULT hr = ifirst.Compare(
                        isecond, SICHINTF.SICHINT_ALLFIELDS, out result);

                    if ((hr == HRESULT.S_OK) && (result == 0))
                        areEqual = true;
                }
            }

            return areEqual;
        }

        /// <summary>
        /// Returns whether this object is equal to another.
        /// </summary>
        /// <param name="obj">The object to compare against.</param>
        /// <returns>Equality result.</returns>
        public override bool Equals(object obj)
        {
            return this.Equals(obj as ShellObject);
        }

        /// <summary>
        /// Implements the == (equality) operator.
        /// </summary>
        /// <param name="a">Object a.</param>
        /// <param name="b">Object b.</param>
        /// <returns>true if object a equals object b; false otherwise.</returns>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "a"), System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "b")]
        public static bool operator ==(ShellObject a, ShellObject b)
        {
            if ((object)a == null)
            {
                return ((object)b == null);
            }
            else
            {
                return a.Equals(b);
            }
        }

        /// <summary>
        /// Implements the != (inequality) operator.
        /// </summary>
        /// <param name="a">Object a.</param>
        /// <param name="b">Object b.</param>
        /// <returns>true if object a does not equal object b; false otherwise.</returns>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "a"), System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "b")]
        public static bool operator !=(ShellObject a, ShellObject b)
        {
            if ((object)a == null)
            {
                return ((object)b != null);
            }
            else
            {
                return !a.Equals(b);
            }
        }


        #endregion
    }
}

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