Windows 7 Taskbar in .NET 2.0

namespace ZetaUploader.WindowsClient.Code.UI
{
    using System;
    using System.Diagnostics;
    using System.Runtime.InteropServices;
    using WindowsClient.UI.Helper;

    // See http://archive.msdn.microsoft.com/Windows7Taskbar/Release/ProjectReleases.aspx?ReleaseId=2246
    // See http://stackoverflow.com/questions/1295890/windows-7-progress-bar-in-taskbar-in-c

    internal static class Windows7Taskbar
    {
        public static uint TaskbarButtonCreatedMessage
        {
            get { return UnsafeNativeMethods.WM_TaskbarButtonCreated; }
        }

        internal enum TBPFLAG
        {
            TBPF_NOPROGRESS = 0,
            TBPF_INDETERMINATE = 0x1,
            TBPF_NORMAL = 0x2,
            TBPF_ERROR = 0x4,
            TBPF_PAUSED = 0x8
        }

        [ComImportAttribute()]
        [GuidAttribute("ea1afb91-9e28-4b86-90e9-9e9f8a5eefaf")]
        [InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
        internal interface ITaskbarList3
        {
            // ITaskbarList
            [PreserveSig]
            void HrInit();
            [PreserveSig]
            void AddTab(IntPtr hwnd);
            [PreserveSig]
            void DeleteTab(IntPtr hwnd);
            [PreserveSig]
            void ActivateTab(IntPtr hwnd);
            [PreserveSig]
            void SetActiveAlt(IntPtr hwnd);

            // ITaskbarList2
            [PreserveSig]
            void MarkFullscreenWindow(
                IntPtr hwnd,
                [MarshalAs(UnmanagedType.Bool)] bool fFullscreen);

            // ITaskbarList3
            void SetProgressValue(IntPtr hwnd, UInt64 ullCompleted, UInt64 ullTotal);
            void SetProgressState(IntPtr hwnd, TBPFLAG tbpFlags);
            void RegisterTab(IntPtr hwndTab, IntPtr hwndMDI);
            void UnregisterTab(IntPtr hwndTab);
            void SetTabOrder(IntPtr hwndTab, IntPtr hwndInsertBefore);
            void SetTabActive(IntPtr hwndTab, IntPtr hwndMDI, TBATFLAG tbatFlags);
            void ThumbBarAddButtons(
                IntPtr hwnd,
                uint cButtons,
                [MarshalAs(UnmanagedType.LPArray)] THUMBBUTTON[] pButtons);
            void ThumbBarUpdateButtons(
                IntPtr hwnd,
                uint cButtons,
                [MarshalAs(UnmanagedType.LPArray)] THUMBBUTTON[] pButtons);
            void ThumbBarSetImageList(IntPtr hwnd, IntPtr himl);
            void SetOverlayIcon(
              IntPtr hwnd,
              IntPtr hIcon,
              [MarshalAs(UnmanagedType.LPWStr)] string pszDescription);
            void SetThumbnailTooltip(
                IntPtr hwnd,
                [MarshalAs(UnmanagedType.LPWStr)] string pszTip);
            void SetThumbnailClip(
                IntPtr hwnd,
                /*[MarshalAs(UnmanagedType.LPStruct)]*/ ref Win32.RECT prcClip);
        }
        [StructLayout(LayoutKind.Sequential)]
        internal struct RECT
        {
            public int left;
            public int top;
            public int right;
            public int bottom;

            public RECT(int left, int top, int right, int bottom)
            {
                this.left = left;
                this.top = top;
                this.right = right;
                this.bottom = bottom;
            }
        }

        internal enum TBATFLAG
        {
            TBATF_USEMDITHUMBNAIL = 0x1,
            TBATF_USEMDILIVEPREVIEW = 0x2
        }

        internal enum THBMASK
        {
            THB_BITMAP = 0x1,
            THB_ICON = 0x2,
            THB_TOOLTIP = 0x4,
            THB_FLAGS = 0x8
        }

        internal enum THBFLAGS
        {
            THBF_ENABLED = 0,
            THBF_DISABLED = 0x1,
            THBF_DISMISSONCLICK = 0x2,
            THBF_NOBACKGROUND = 0x4,
            THBF_HIDDEN = 0x8
        }

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        internal struct THUMBBUTTON
        {
            [MarshalAs(UnmanagedType.U4)]
            public THBMASK dwMask;
            public uint iId;
            public uint iBitmap;
            public IntPtr hIcon;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
            public string szTip;
            [MarshalAs(UnmanagedType.U4)]
            public THBFLAGS dwFlags;
        }

        [GuidAttribute(@"56FDF344-FD6D-11d0-958A-006097C9A090")]
        [ClassInterfaceAttribute(ClassInterfaceType.None)]
        [ComImportAttribute]
        internal class CTaskbarList { }

        private static ITaskbarList3 _taskbarList;
        private static bool _everTried;
        private static bool _windows7;
        private static bool _everCheckedWindows7;

        private static ITaskbarList3 TaskbarList
        {
            get
            {
                if (_taskbarList == null && !_everTried)
                {
                    lock (typeof(Windows7Taskbar))
                    {
                        if (_taskbarList == null)
                        {
                            try
                            {
                                _taskbarList = (ITaskbarList3)new CTaskbarList();
                                _taskbarList.HrInit();
                            }
                            catch (Exception x)
                            {
                                Trace.TraceError(x.Message);
                                _everTried = true;
                            }
                        }
                    }
                }
                return _taskbarList;
            }
        }


        #region Taskbar Progress Bar

        /// <summary>
        /// Represents the thumbnail progress bar state.
        /// </summary>
        public enum ThumbnailProgressState
        {
            /// <summary>
            /// No progress is displayed.
            /// </summary>
            NoProgress = 0,
            /// <summary>
            /// The progress is indeterminate (marquee).
            /// </summary>
            Indeterminate = 0x1,
            /// <summary>
            /// Normal progress is displayed.
            /// </summary>
            Normal = 0x2,
            /// <summary>
            /// An error occurred (red).
            /// </summary>
            Error = 0x4,
            /// <summary>
            /// The operation is paused (yellow).
            /// </summary>
            Paused = 0x8
        }

        private static bool isRunningOnWindows7
        {
            get
            {
                //return true;
                if (!_everCheckedWindows7)
                {
                    _windows7 =
                        Environment.OSVersion.Version.Major >= 6 &&
                        Environment.OSVersion.Version.Major >= 1 /*&&
                        TaskbarList != null*/;
                    _everCheckedWindows7 = true;
                }

                return _windows7;
            }
        }

        public static void SetProgressState(IntPtr hwnd,
            ThumbnailProgressState state)
        {
            if (isRunningOnWindows7 && TaskbarList!=null)
            {
                TaskbarList.SetProgressState(hwnd, (TBPFLAG)state);
            }
        }

        public static void SetProgressValue(IntPtr hwnd,
            ulong current, ulong maximum)
        {
            if (isRunningOnWindows7 && TaskbarList != null)
            {
                TaskbarList.SetProgressValue(hwnd, current, maximum);
            }
        }

        #endregion

        //public static void AllowTaskbarWindowMessagesThroughUIPI()
        //{
        //    if (isRunningOnWindows7)
        //    {
        //        UnsafeNativeMethods.ChangeWindowMessageFilter(
        //            UnsafeNativeMethods.WM_TaskbarButtonCreated,
        //            SafeNativeMethods.MSGFLT_ADD);
        //        UnsafeNativeMethods.ChangeWindowMessageFilter(
        //            SafeNativeMethods.WM_DWMSENDICONICTHUMBNAIL,
        //            SafeNativeMethods.MSGFLT_ADD);
        //        UnsafeNativeMethods.ChangeWindowMessageFilter(
        //            SafeNativeMethods.WM_DWMSENDICONICLIVEPREVIEWBITMAP,
        //            SafeNativeMethods.MSGFLT_ADD);
        //        UnsafeNativeMethods.ChangeWindowMessageFilter(
        //            SafeNativeMethods.WM_COMMAND,
        //            SafeNativeMethods.MSGFLT_ADD);
        //        UnsafeNativeMethods.ChangeWindowMessageFilter(
        //            SafeNativeMethods.WM_SYSCOMMAND,
        //            SafeNativeMethods.MSGFLT_ADD);
        //        UnsafeNativeMethods.ChangeWindowMessageFilter(
        //            SafeNativeMethods.WM_ACTIVATE,
        //            SafeNativeMethods.MSGFLT_ADD);
        //    }
        //}

        //public static void SetCurrentProcessAppId(string appId)
        //{
        //    if (isRunningOnWindows7)
        //    {
        //        UnsafeNativeMethods.SetCurrentProcessExplicitAppUserModelID(appId);
        //    }
        //}
    }
}