根据文件名和扩展名获得该文件的图标

C# 代码

using  System;
using  System.Collections.Generic;
using  System.Text;
using  System.Runtime.InteropServices;
using  System.Drawing;

namespace  WindowsApplication
... {
    /**////   <summary>   
    ///   Summary   description   for   ExtractIcon.   
    ///   </summary>   
    public class ExtractIcon
    ...{
        [DllImport("Shell32.dll")]
        private static extern int SHGetFileInfo
        (
        string pszPath,
        uint dwFileAttributes,
        out   SHFILEINFO psfi,
        uint cbfileInfo,
        SHGFI uFlags
        );

        [StructLayout(LayoutKind.Sequential)]
        private struct SHFILEINFO
        ...{
            public SHFILEINFO(bool b)
            ...{
                hIcon = IntPtr.Zero; iIcon = 0; dwAttributes = 0; szDisplayName = ""; szTypeName = "";
            }
            public IntPtr hIcon;
            public int iIcon;
            public uint dwAttributes;
            [MarshalAs(UnmanagedType.LPStr, SizeConst = 260)]
            public string szDisplayName;
            [MarshalAs(UnmanagedType.LPStr, SizeConst = 80)]
            public string szTypeName;
        };

        private ExtractIcon()
        ...{
        }

        private enum SHGFI
        ...{
            SmallIcon = 0x00000001,
            LargeIcon = 0x00000000,
            Icon = 0x00000100,
            DisplayName = 0x00000200,
            Typename = 0x00000400,
            SysIconIndex = 0x00004000,
            UseFileAttributes = 0x00000010
        }

        /**////   <summary>   
        ///   Get   the   associated   Icon   for   a   file   or   application,   this   method   always returns   
        ///   an   icon.     If   the   strPath   is   invalid   or   there   is   no   idonc   the   default icon   is   returned   
        ///   </summary>   
        ///   <param   name="strPath">full   path   to   the   file</param>   
        ///   <param   name="bSmall">if   true,   the   16x16   icon   is   returned   otherwise   the 32x32</param>   
        ///   <returns></returns>   
        public static Icon GetIcon(string strPath, bool bSmall)
        ...{
            SHFILEINFO info = new SHFILEINFO(true);
            int cbFileInfo = Marshal.SizeOf(info);
            SHGFI flags;
            if (bSmall)
                flags = SHGFI.Icon | SHGFI.SmallIcon | SHGFI.UseFileAttributes;
            else
                flags = SHGFI.Icon | SHGFI.LargeIcon | SHGFI.UseFileAttributes;

            SHGetFileInfo(strPath, 256, out   info, (uint)cbFileInfo, flags);
            return Icon.FromHandle(info.hIcon);
        }
    }
}