C#中如何获取文件图标

string fileName = "tmp." + houzhuiming;
　　　　File.Create(fileName).Close();
　　　　Image img = System.Drawing.Icon.ExtractAssociatedIcon(fileName).ToBitmap();
　　　　File.Delete(fileName);

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Drawing;
using Microsoft.Win32;
namespace ifmdp.DeviceManager
{
class SystemIcon
{
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public struct SHFILEINFO
{
public IntPtr hIcon;
public int iIcon;
public uint dwAttributes;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
public string szDisplayName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
public string szTypeName;
}
[DllImport("Shell32.dll", EntryPoint = "SHGetFileInfo", SetLastError = true, CharSet = CharSet.Auto)]
public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbFileInfo, uint uFlags);
[DllImport("User32.dll", EntryPoint = "DestroyIcon")]
public static extern int DestroyIcon(IntPtr hIcon);
#region API 参数的常量定义
public enum FileInfoFlags : uint
{
SHGFI_ICON = 0x000000100, // get icon
SHGFI_DISPLAYNAME = 0x000000200, // get display name
SHGFI_TYPENAME = 0x000000400, // get type name
SHGFI_ATTRIBUTES = 0x000000800, // get attributes
SHGFI_ICONLOCATION = 0x000001000, // get icon location
SHGFI_EXETYPE = 0x000002000, // return exe type
SHGFI_SYSICONINDEX = 0x000004000, // get system icon index
SHGFI_LINKOVERLAY = 0x000008000, // put a link overlay on icon
SHGFI_SELECTED = 0x000010000, // show icon in selected state
SHGFI_ATTR_SPECIFIED = 0x000020000, // get only specified attributes
SHGFI_LARGEICON = 0x000000000, // get large icon
SHGFI_SMALLICON = 0x000000001, // get small icon
SHGFI_OPENICON = 0x000000002, // get open icon
SHGFI_SHELLICONSIZE = 0x000000004, // get shell size icon
SHGFI_PIDL = 0x000000008, // pszPath is a pidl
SHGFI_USEFILEATTRIBUTES = 0x000000010, // use passed dwFileAttribute
SHGFI_ADDOVERLAYS = 0x000000020, // apply the appropriate overlays
SHGFI_OVERLAYINDEX = 0x000000040 // Get the index of the overlay
}
public enum FileAttributeFlags : uint
{
FILE_ATTRIBUTE_READONLY = 0x00000001,
FILE_ATTRIBUTE_HIDDEN = 0x00000002,
FILE_ATTRIBUTE_SYSTEM = 0x00000004,
FILE_ATTRIBUTE_DIRECTORY = 0x00000010,
FILE_ATTRIBUTE_ARCHIVE = 0x00000020,
FILE_ATTRIBUTE_DEVICE = 0x00000040,
FILE_ATTRIBUTE_NORMAL = 0x00000080,
FILE_ATTRIBUTE_TEMPORARY = 0x00000100,
FILE_ATTRIBUTE_SPARSE_FILE = 0x00000200,
FILE_ATTRIBUTE_REPARSE_POINT = 0x00000400,
FILE_ATTRIBUTE_COMPRESSED = 0x00000800,
FILE_ATTRIBUTE_OFFLINE = 0x00001000,
FILE_ATTRIBUTE_NOT_CONTENT_INDEXED = 0x00002000,
FILE_ATTRIBUTE_ENCRYPTED = 0x00004000
}
#endregion
/// <summary>
/// 获取文件类型的关联图标
/// </summary>
/// <param name="fileName">文件类型的扩展名或文件的绝对路径</param>
/// <param name="isLargeIcon">是否返回大图标</param>
/// <returns>获取到的图标</returns>
public static Icon GetIcon(string fileName, bool isLargeIcon)
{
SHFILEINFO shfi = new SHFILEINFO();
IntPtr hI;
if (isLargeIcon)
hI = SHGetFileInfo(fileName, 0, ref shfi, (uint)Marshal.SizeOf(shfi), (uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_USEFILEATTRIBUTES | (uint)FileInfoFlags.SHGFI_LARGEICON);
else
hI = SHGetFileInfo(fileName, 0, ref shfi, (uint)Marshal.SizeOf(shfi), (uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_USEFILEATTRIBUTES | (uint)FileInfoFlags.SHGFI_SMALLICON);
Icon icon = Icon.FromHandle(shfi.hIcon).Clone() as Icon;
DestroyIcon(shfi.hIcon); //释放资源
return icon;
}
/// <summary> 
/// 获取文件夹图标
/// </summary> 
/// <returns>图标</returns> 
public static Icon GetDirectoryIcon(bool isLargeIcon)
{
SHFILEINFO _SHFILEINFO = new SHFILEINFO();
IntPtr _IconIntPtr;
if (isLargeIcon)
{
_IconIntPtr = SHGetFileInfo(@"", 0, ref _SHFILEINFO, (uint)Marshal.SizeOf(_SHFILEINFO), ((uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_LARGEICON));
}
else
{
_IconIntPtr = SHGetFileInfo(@"", 0, ref _SHFILEINFO, (uint)Marshal.SizeOf(_SHFILEINFO), ((uint)FileInfoFlags.SHGFI_ICON | (uint)FileInfoFlags.SHGFI_SMALLICON));
}
if (_IconIntPtr.Equals(IntPtr.Zero)) return null;
Icon _Icon = System.Drawing.Icon.FromHandle(_SHFILEINFO.hIcon);
return _Icon;
}
}
}