/// <summary>
        /// Shows the folder browser dialog box with the specified owner window.
        /// </summary>
        public DialogResult ShowDialog(IWin32Window owner) {
            IntPtr pidlRoot = IntPtr.Zero;

            // Get/find an owner HWND for this dialog.
            IntPtr hWndOwner;

            if (owner != null) {
                hWndOwner = owner.Handle;
            } else {
                hWndOwner = WinAPI.GetActiveWindow();
            }

            // Get the IDL for the specific startLocation.
            WinAPI.Shell32.SHGetSpecialFolderLocation(hWndOwner, (int)startLocation, out pidlRoot);

            if (pidlRoot == IntPtr.Zero) {
                return DialogResult.Cancel;
            }

            int mergedOptions = (int)publicOptions | (int)privateOptions;

            if ((mergedOptions & (int)WinAPI.Shell32.BffStyles.NewDialogStyle) != 0) {
                if (System.Threading.ApartmentState.MTA == Application.OleRequired())
                    mergedOptions = mergedOptions & (~(int)WinAPI.Shell32.BffStyles.NewDialogStyle);
            }

            IntPtr pidlRet = IntPtr.Zero;

            try {
                // Construct a BROWSEINFO.
                WinAPI.Shell32.BROWSEINFO bi = new WinAPI.Shell32.BROWSEINFO();
                IntPtr buffer = Marshal.AllocHGlobal(MAX_PATH);

                bi.pidlRoot = pidlRoot;
                bi.hwndOwner = hWndOwner;
                bi.pszDisplayName = buffer;
                bi.lpszTitle = descriptionText;
                bi.ulFlags = mergedOptions;
                // The rest of the fields are initialized to zero by the constructor.
                // bi.lpfn = null;  bi.lParam = IntPtr.Zero;    bi.iImage = 0;

                // Show the dialog.
                pidlRet = WinAPI.Shell32.SHBrowseForFolder(ref bi);

                // Free the buffer you've allocated on the global heap.
                Marshal.FreeHGlobal(buffer);

                if (pidlRet == IntPtr.Zero) {
                    // User clicked Cancel.
                    return DialogResult.Cancel;
                }

                // Then retrieve the path from the IDList.
                StringBuilder sb = new StringBuilder(MAX_PATH);
                if (0 == WinAPI.Shell32.SHGetPathFromIDList(pidlRet, sb)) {
                    return DialogResult.Cancel;
                }

                // Convert to a string.
                directoryPath = sb.ToString();
            } finally {
                WinAPI.IMalloc malloc = GetSHMalloc();
                malloc.Free(pidlRoot);

                if (pidlRet != IntPtr.Zero) {
                    malloc.Free(pidlRet);
                }
            }

            return DialogResult.OK;
        }
        /// <summary>
        /// Shows the folder browser dialog box with the specified owner window.
        /// </summary>
        public DialogResult ShowDialog(IWin32Window owner)
        {
            IntPtr pidlRoot = IntPtr.Zero;

            // Get/find an owner HWND for this dialog.
            IntPtr hWndOwner;

            if (owner != null)
            {
                hWndOwner = owner.Handle;
            }
            else
            {
                hWndOwner = WinAPI.GetActiveWindow();
            }

            // Get the IDL for the specific startLocation.
            WinAPI.Shell32.SHGetSpecialFolderLocation(hWndOwner, (int)startLocation, out pidlRoot);

            if (pidlRoot == IntPtr.Zero)
            {
                return(DialogResult.Cancel);
            }

            int mergedOptions = (int)publicOptions | (int)privateOptions;

            if ((mergedOptions & (int)WinAPI.Shell32.BffStyles.NewDialogStyle) != 0)
            {
                if (System.Threading.ApartmentState.MTA == Application.OleRequired())
                {
                    mergedOptions = mergedOptions & (~(int)WinAPI.Shell32.BffStyles.NewDialogStyle);
                }
            }

            IntPtr pidlRet = IntPtr.Zero;

            try {
                // Construct a BROWSEINFO.
                WinAPI.Shell32.BROWSEINFO bi = new WinAPI.Shell32.BROWSEINFO();
                IntPtr buffer = Marshal.AllocHGlobal(MAX_PATH);

                bi.pidlRoot       = pidlRoot;
                bi.hwndOwner      = hWndOwner;
                bi.pszDisplayName = buffer;
                bi.lpszTitle      = descriptionText;
                bi.ulFlags        = mergedOptions;
                // The rest of the fields are initialized to zero by the constructor.
                // bi.lpfn = null;  bi.lParam = IntPtr.Zero;    bi.iImage = 0;

                // Show the dialog.
                pidlRet = WinAPI.Shell32.SHBrowseForFolder(ref bi);

                // Free the buffer you've allocated on the global heap.
                Marshal.FreeHGlobal(buffer);

                if (pidlRet == IntPtr.Zero)
                {
                    // User clicked Cancel.
                    return(DialogResult.Cancel);
                }

                // Then retrieve the path from the IDList.
                StringBuilder sb = new StringBuilder(MAX_PATH);
                if (0 == WinAPI.Shell32.SHGetPathFromIDList(pidlRet, sb))
                {
                    return(DialogResult.Cancel);
                }

                // Convert to a string.
                directoryPath = sb.ToString();
            } finally {
                WinAPI.IMalloc malloc = GetSHMalloc();
                malloc.Free(pidlRoot);

                if (pidlRet != IntPtr.Zero)
                {
                    malloc.Free(pidlRet);
                }
            }

            return(DialogResult.OK);
        }