[.NET3.5] EXTENSION METHODS: PROGRESSBAR ET VISTA

using System;
using System.Runtime.InteropServices;

namespace ExtensionMethods
{
    public static class Progressbar
    {
        #region "Native methods"

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
        private static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

        [DllImport("user32.dll", EntryPoint = "GetWindowLong", SetLastError = true)]
        private static extern IntPtr GetWindowLong32(IntPtr hWnd, int nIndex);

        [DllImport("user32.dll", SetLastError = true)]
        private static extern IntPtr GetWindowLongPtr(IntPtr hWnd, int nIndex);

        [DllImport("user32.dll", EntryPoint = "SetWindowLong", SetLastError = true)]
        private static extern int SetWindowLong32(IntPtr hWnd, int nIndex, int dwNewLong);

        [DllImport("user32.dll", SetLastError = true)]
        private static extern IntPtr SetWindowLongPtr(IntPtr hWnd, int nIndex, IntPtr dwNewLong);

        const int WM_USER = 0x400;
        const int GWL_STYLE = (-16);
        const int PBM_SETPOS = (WM_USER + 2);
        const int PBM_SETSTATE = (WM_USER + 16);
        const int PBM_GETSTATE = (WM_USER + 17);
        const int PBS_SMOOTH = 0x01;
        const int PBS_SMOOTHREVERSE = 0x10;

        #endregion

        /// <summary>
        /// Etat de la barre de progression.
        /// </summary>
        public enum PBM_STATE : int
        {
            NORMAL = 0x1,
            ERROR,
            PAUSE
        }

        /// <summary>
        /// Obtient l'état de la barre de progression.
        /// </summary>
        /// <param name="pb"><see cref="System.Windows.Forms.ProgressBar"/></param>
        /// <returns>L'état <see cref="PBM_STATE"/>.</returns>
        public static PBM_STATE GetState(this System.Windows.Forms.ProgressBar pb)
        {
            if (Environment.OSVersion.Version.Major >= 6)
            {
                IntPtr pValue = SendMessage(pb.Handle, PBM_GETSTATE, IntPtr.Zero, IntPtr.Zero);

                int iVal = pValue.ToInt32();
                return (PBM_STATE)iVal;
            }
            else
                throw new Exception("Supported on Vista or later only !.");
        }

        /// <summary>
        /// Définit l'état de la barre de progression.
        /// </summary>
        /// <param name="pb"><see cref="System.Windows.Forms.ProgressBar"/></param>
        /// <param name="state">Nouvel état <see cref="PBM_STATE"/>.</param>
        public static void SetState(this System.Windows.Forms.ProgressBar pb, PBM_STATE state)
        {
            if (Environment.OSVersion.Version.Major >= 6)
            {
                SendMessage(pb.Handle, PBM_SETSTATE, new IntPtr((int)state), IntPtr.Zero);
            }
            else
                throw new Exception("Supported on Vista or later only !.");
        }

        /// <summary>
        /// Change la manière dont la décrémentation de la valeur de la progress bar se fait.
        /// </summary>
        /// <param name="pb"><see cref="System.Windows.Forms.ProgressBar"/></param>
        /// <param name="turnOn"><b>True</b> pour décrémentation fluide; <b>False</b> pour décrémentation direct.</param>
        public static void SmoothReverse(this System.Windows.Forms.ProgressBar pb, bool turnOn)
        {
            if (Environment.OSVersion.Version.Major >= 6)
            {
                //Récupère le style.
                IntPtr pStyle = GetWindowLong(pb.Handle, GWL_STYLE);

                //Garde la valeur actuelle pour redéfinir celle de la progress bar une fois la modification de style effectué.
                int iOldVal = pb.Value;

                if (turnOn)
                {
                    //Si pas activé?
                    //On active.
                    if ((pStyle.ToInt32() & PBS_SMOOTHREVERSE) != PBS_SMOOTHREVERSE)
                    {
                        SetWindowLong(pb.Handle, GWL_STYLE, new IntPtr((pStyle.ToInt32() | PBS_SMOOTHREVERSE)));
                        SendMessage(pb.Handle, PBM_SETPOS, new IntPtr(iOldVal), IntPtr.Zero);
                    }
                }
                else
                {
                    //Si activé?
                    //On désactive.
                    if ((pStyle.ToInt32() & PBS_SMOOTHREVERSE) == PBS_SMOOTHREVERSE)
                    {
                        SetWindowLong(pb.Handle, GWL_STYLE, new IntPtr((pStyle.ToInt32() - PBS_SMOOTHREVERSE)));
                        SendMessage(pb.Handle, PBM_SETPOS, new IntPtr(iOldVal), IntPtr.Zero);
                    }
                }
            }
            else
                throw new Exception("Supported on Vista or later only !.");
        }

        /// <summary>
        /// GetWindowLong avec support 32 et 64 bits.
        /// </summary>
        private static IntPtr GetWindowLong(IntPtr hWnd, int nIndex)
        {
            if (IntPtr.Size == 8)
                return GetWindowLongPtr(hWnd, nIndex);
            else
                return GetWindowLong32(hWnd, nIndex);
        }

        /// <summary>
        /// SetWindowLong avec support 32 et 64 bits.
        /// </summary>
        private static IntPtr SetWindowLong(IntPtr hWnd, int nIndex, IntPtr dwNewLong)
        {
            if (IntPtr.Size == 8)
                return SetWindowLongPtr(hWnd, nIndex, dwNewLong);
            else
                return new IntPtr(SetWindowLong32(hWnd, nIndex, dwNewLong.ToInt32()));
        }
    }
}