gistfile1.cs

        //The might .dll shell32 behold !
        [DllImport("Shell32.dll")]
        public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, int cbFileInfo, uint uFlags);
        // Constants that we need in the function call
        private const int SHGFI_ICON = 0x100;
        private const int SHGFI_SMALLICON = 0x1;
        private const int SHGFI_LARGEICON = 0x0;
        
        // This structure will contain information about the file
        public struct SHFILEINFO
        {
            // Handle to the icon representing the file
            public IntPtr hIcon;
            // Index of the icon within the image list
            public int iIcon;
            // Various attributes of the file
            public uint dwAttributes;
            // Path to the file
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string szDisplayName;
            // File type
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
            public string szTypeName;
        };
        //Sample Usage, not (to) advanced ? =)
          private void DrawIcon(string strFilePath)
        {
           //Store the 'Icon' 
            Icon myIcon;
            //Large icon
            IntPtr hImgLarge;
            //;) fancy shit
            SHFILEINFO shinfo = new SHFILEINFO();

            ///////////////////////////////
            //DRAW THE LARGE ICON
            ///////////////////////////////
            //Get handle
            hImgLarge = SHGetFileInfo(txtFilePath.Text, 0, ref shinfo, Marshal.SizeOf(shinfo), SHGFI_ICON | SHGFI_LARGEICON);
            //myIcon equal icon from file
            myIcon = Icon.FromHandle(shinfo.hIcon);
            //Draw icon inside picture box
            picLarge.Image = myIcon.ToBitmap();
            //Clean up and jump out 
            GC.Collect();
        }