MARKUS

using System;

using System.Drawing;

using System.Collections;

using System.ComponentModel;

using System.Data;

using System.Runtime.InteropServices;

namespace Etier.IconHelper

{

    /// <summary>

    /// Provides static methods to read system icons for both folders and files.

    /// </summary>

    /// <example>

    /// <code>IconReader.GetFileIcon("c:\\general.xls");</code>

    /// </example>

    public class IconReader

    {

        /// <summary>

        /// Options to specify the size of icons to return.

        /// </summary>

        public enum IconSize

        {

            /// <summary>

            /// Specify large icon - 32 pixels by 32 pixels.

            /// </summary>

            Large = 0,

            /// <summary>

            /// Specify small icon - 16 pixels by 16 pixels.

            /// </summary>

            Small = 1

        }

        /// <summary>

        /// Options to specify whether folders should be in the open or closed state.

        /// </summary>

        public enum FolderType

        {

            /// <summary>

            /// Specify open folder.

            /// </summary>

            Open = 0,

            /// <summary>

            /// Specify closed folder.

            /// </summary>

            Closed = 1

        }

        /// <summary>

        /// Returns an icon for a given file - indicated by the name parameter.

        /// </summary>

        /// <param name="name">Pathname for file.</param>

        /// <param name="size">Large or small</param>

        /// <param name="linkOverlay">Whether to include the link icon</param>

        /// <returns>System.Drawing.Icon</returns>

        public static System.Drawing.Icon GetFileIcon(string name, IconSize size, bool linkOverlay)

        {

            Shell32.SHFILEINFO shfi = new Shell32.SHFILEINFO();

            uint flags = Shell32.SHGFI_ICON | Shell32.SHGFI_USEFILEATTRIBUTES;

            if (true == linkOverlay) flags += Shell32.SHGFI_LINKOVERLAY;

            /* Check the size specified for return. */

            if (IconSize.Small == size)

            {

                flags += Shell32.SHGFI_SMALLICON;

            }

            else

            {

                flags += Shell32.SHGFI_LARGEICON;

            }

            Shell32.SHGetFileInfo(name,

                Shell32.FILE_ATTRIBUTE_NORMAL,

                ref shfi,

                (uint)System.Runtime.InteropServices.Marshal.SizeOf(shfi),

                flags);

            // Copy (clone) the returned icon to a new object, thus allowing us to clean-up properly

            System.Drawing.Icon icon = (System.Drawing.Icon)System.Drawing.Icon.FromHandle(shfi.hIcon).Clone();

            User32.DestroyIcon(shfi.hIcon);     // Cleanup

            return icon;

        }

        /// <summary>

        /// Used to access system folder icons.

        /// </summary>

        /// <param name="size">Specify large or small icons.</param>

        /// <param name="folderType">Specify open or closed FolderType.</param>

        /// <returns>System.Drawing.Icon</returns>

        public static System.Drawing.Icon GetFolderIcon(IconSize size, FolderType folderType)

        {

            // Need to add size check, although errors generated at present!

            uint flags = Shell32.SHGFI_ICON | Shell32.SHGFI_USEFILEATTRIBUTES;

            if (FolderType.Open == folderType)

            {

                flags += Shell32.SHGFI_OPENICON;

            }

            if (IconSize.Small == size)

            {

                flags += Shell32.SHGFI_SMALLICON;

            }

            else

            {

                flags += Shell32.SHGFI_LARGEICON;

            }

            // Get the folder icon

            Shell32.SHFILEINFO shfi = new Shell32.SHFILEINFO();

            Shell32.SHGetFileInfo(null,

                Shell32.FILE_ATTRIBUTE_DIRECTORY,

                ref shfi,

                (uint)System.Runtime.InteropServices.Marshal.SizeOf(shfi),

                flags);

            System.Drawing.Icon.FromHandle(shfi.hIcon); // Load the icon from an HICON handle

            // Now clone the icon, so that it can be successfully stored in an ImageList

            System.Drawing.Icon icon = (System.Drawing.Icon)System.Drawing.Icon.FromHandle(shfi.hIcon).Clone();

            User32.DestroyIcon(shfi.hIcon);     // Cleanup

            return icon;

        }

    }

    /// <summary>

    /// Wraps necessary Shell32.dll structures and functions required to retrieve Icon Handles using SHGetFileInfo. Code

    /// courtesy of MSDN Cold Rooster Consulting case study.

    /// </summary>

    /// 

    // This code has been left largely untouched from that in the CRC example. The main changes have been moving

    // the icon reading code over to the IconReader type.

    public class Shell32

    {

        public const int MAX_PATH = 256;

        [StructLayout(LayoutKind.Sequential)]

        public struct SHITEMID

        {

            public ushort cb;

            [MarshalAs(UnmanagedType.LPArray)]

            public byte[] abID;

        }

        [StructLayout(LayoutKind.Sequential)]

        public struct ITEMIDLIST

        {

            public SHITEMID mkid;

        }

        [StructLayout(LayoutKind.Sequential)]

        public struct BROWSEINFO

        {

            public IntPtr hwndOwner;

            public IntPtr pidlRoot;

            public IntPtr pszDisplayName;

            [MarshalAs(UnmanagedType.LPTStr)]

            public string lpszTitle;

            public uint ulFlags;

            public IntPtr lpfn;

            public int lParam;

            public IntPtr iImage;

        }

        // Browsing for directory.

        public const uint BIF_RETURNONLYFSDIRS = 0x0001;

        public const uint BIF_DONTGOBELOWDOMAIN = 0x0002;

        public const uint BIF_STATUSTEXT = 0x0004;

        public const uint BIF_RETURNFSANCESTORS = 0x0008;

        public const uint BIF_EDITBOX = 0x0010;

        public const uint BIF_VALIDATE = 0x0020;

        public const uint BIF_NEWDIALOGSTYLE = 0x0040;

        public const uint BIF_USENEWUI = (BIF_NEWDIALOGSTYLE | BIF_EDITBOX);

        public const uint BIF_BROWSEINCLUDEURLS = 0x0080;

        public const uint BIF_BROWSEFORCOMPUTER = 0x1000;

        public const uint BIF_BROWSEFORPRINTER = 0x2000;

        public const uint BIF_BROWSEINCLUDEFILES = 0x4000;

        public const uint BIF_SHAREABLE = 0x8000;

        [StructLayout(LayoutKind.Sequential)]

        public struct SHFILEINFO

        {

            public const int NAMESIZE = 80;

            public IntPtr hIcon;

            public int iIcon;

            public uint dwAttributes;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_PATH)]

            public string szDisplayName;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = NAMESIZE)]

            public string szTypeName;

        };

        public const uint SHGFI_ICON = 0x000000100;     // get icon

        public const uint SHGFI_DISPLAYNAME = 0x000000200;     // get display name

        public const uint SHGFI_TYPENAME = 0x000000400;     // get type name

        public const uint SHGFI_ATTRIBUTES = 0x000000800;     // get attributes

        public const uint SHGFI_ICONLOCATION = 0x000001000;     // get icon location

        public const uint SHGFI_EXETYPE = 0x000002000;     // return exe type

        public const uint SHGFI_SYSICONINDEX = 0x000004000;     // get system icon index

        public const uint SHGFI_LINKOVERLAY = 0x000008000;     // put a link overlay on icon

        public const uint SHGFI_SELECTED = 0x000010000;     // show icon in selected state

        public const uint SHGFI_ATTR_SPECIFIED = 0x000020000;     // get only specified attributes

        public const uint SHGFI_LARGEICON = 0x000000000;     // get large icon

        public const uint SHGFI_SMALLICON = 0x000000001;     // get small icon

        public const uint SHGFI_OPENICON = 0x000000002;     // get open icon

        public const uint SHGFI_SHELLICONSIZE = 0x000000004;     // get shell size icon

        public const uint SHGFI_PIDL = 0x000000008;     // pszPath is a pidl

        public const uint SHGFI_USEFILEATTRIBUTES = 0x000000010;     // use passed dwFileAttribute

        public const uint SHGFI_ADDOVERLAYS = 0x000000020;     // apply the appropriate overlays

        public const uint SHGFI_OVERLAYINDEX = 0x000000040;     // Get the index of the overlay

        public const uint FILE_ATTRIBUTE_DIRECTORY = 0x00000010;

        public const uint FILE_ATTRIBUTE_NORMAL = 0x00000080;

        [DllImport("Shell32.dll")]

        public static extern IntPtr SHGetFileInfo(

            string pszPath,

            uint dwFileAttributes,

            ref SHFILEINFO psfi,

            uint cbFileInfo,

            uint uFlags

            );

    }

    /// <summary>

    /// Wraps necessary functions imported from User32.dll. Code courtesy of MSDN Cold Rooster Consulting example.

    /// </summary>

    public class User32

    {

        /// <summary>

        /// Provides access to function required to delete handle. This method is used internally

        /// and is not required to be called separately.

        /// </summary>

        /// <param name="hIcon">Pointer to icon handle.</param>

        /// <returns>N/A</returns>

        [DllImport("User32.dll")]

        public static extern int DestroyIcon(IntPtr hIcon);

    }

}