C # reading system file icons

Using System;
Using System. Collections;
Using System. Text;
Using System. Runtime. InteropServices;
Using System. Drawing;

Namespace TOA. Common
{
 /// <Summary>
 /// Summary of GetIcon.
 /// </Summary>
 Public class ShellImages
 {

  # Region DLLIMPORT
  // Retrieves information about an object in the file system,
  // Such as a file, a folder, a directory, or a drive root.
  [DllImport ("shell32 ",
   EntryPoint = "SHGetFileInfo ",
   ExactSpelling = false,
   CharSet = CharSet. Auto,
   SetLastError = true)]
  Private static extern IntPtr SHGetFileInfo (
   String pszPath,     // Specify the file name
   FILE_ATTRIBUTE dwFileAttributes,// File attributes
   Ref SHFILEINFO sfi,    // Return the obtained file information, which is a record type
   Int cbFileInfo,     // File type name
   SHGFI uFlags );
  # Endregion

  # Region STRUCTS
  // Contains information about a file object
  [StructLayout (LayoutKind. Sequential, CharSet = CharSet. Auto)]
  Private struct SHFILEINFO
  {
   Public IntPtr hIcon;   // File icon handle
   Public IntPtr iIcon;   // System index number of the icon
   Public uint dwAttributes;  // File property value
   [Financialas (UnmanagedType. ByValTStr, SizeConst = 260)]
   Public string szDisplayName; // File display name
   [Financialas (UnmanagedType. ByValTStr, SizeConst = 80)]
   Public string szTypeName;  // File type name
  };
  # Endregion

  # Region Enums
  // Flags that specify the file information to retrieve with SHGetFileInfo
  [Flags]
  Public enum SHGFI: uint
  {
   ADDOVERLAYS = 0x20,
   ATTR_SPECIFIED = 0x20000,
   ATTRIBUTES = 0x800,  // Obtain attributes
   DISPLAYNAME = 0x200, // Obtain the display name
   EXETYPE = 0x2000,
   ICON = 0x100,   // Get the icon
   ICONLOCATION = 0x1000,
   LARGEICON = 0,   // Get the big icon
   LINKOVERLAY = 0x8000,
   OPENICON = 2,
   OVERLAYINDEX = 0x40,
   PIDL = 8,
   SELECTED = 0x10000,
   SHELLICONSIZE = 4,
   SMALLICON = 1,   // Obtain the small icon
   SYSICONINDEX = 0x4000,
   TYPENAME = 0x400,  // Obtain the type name
   USEFILEATTRIBUTES = 0x10
  }
  // Flags that specify the file information to retrieve with SHGetFileInfo
  [Flags]
  Public enum FILE_ATTRIBUTE
  {
   READONLY = 0x00000001,
   Hiding = 0x00000002,
   SYSTEM = 0x00000004,
   DIRECTORY = 0x00000010,
   ARCHIVE = 0x00000020,
   DEVICE = 0x00000040,
   NORMAL = 0x00000080,
   TEMPORARY = 0x00000100,
   SPARSE_FILE = 0x00000200,
   REPARSE_POINT = 0x00000400,
   COMPRESSED = 0x00000800,
   OFFLINE = 0x00001000,
   NOT_CONTENT_INDEXED = 0x00002000,
   ENCRYPTED = 0x00004000
  }
  # Endregion

  # Region Variables
  // Save the small icon list
  Private static System. Windows. Forms. ImageList smallImageList;
  // Save the large icon list
  Private static System. Windows. Forms. ImageList largeImageList;
  Static ShellImages ()
  {
   SmallImageList = new System. Windows. Forms. ImageList ();
   LargeImageList = new System. Win