本文给大家介绍如何去获取一个文件的关联图标呢？现总结如下：
首先明确问题：获取一个文件的关联图标或者是某个类型文件的显示图标。
在网上搜了一圈，发现方法还是比较多的，但是应用C#进行获取的方法不多。我选择一种用.Net库的方法。
使用的类：
System.Drawing.Icon ，位于System.Drawing 命名空间。
具体方法：
System.Drawing.Icon 类中的静态方法：public static Icon ExtractAssociatedIcon(string filePath)
此方法接收一个文件路径，返回一个 Icon 类型的对象。此对象既是指定文件的 Icon 图标对象。
此 Icon 类提供了 Save 方法，可以将 Icon 文件写入流中，进而保存至硬盘文件。
当然要在程序中显示也是可以的，Icon 类提供了 ToBitmap 方法，可以将 Icon 文件转换为 Bitmap。Bitmap 就可以在 PictureBox 中显示了。
如果要根据后缀名来获取文件图标，那要怎么办呢？我想了一个比较笨的办法。看代码~
string fileName = "tmp." + houzhuiming; File.Create(fileName).Close(); Image img = System.Drawing.Icon.ExtractAssociatedIcon(fileName).ToBitmap(); File.Delete(fileName);
如此，新建一个指定后缀名的文件，获取图标后直接删除，就能获得指定文件后缀名的图标了。嘻嘻~
下面给大家分享一段代码介绍C#获取文件关联图标
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 iconSHGFI_DISPLAYNAME = 0x000000200, // get display nameSHGFI_TYPENAME = 0x000000400, // get type nameSHGFI_ATTRIBUTES = 0x000000800, // get attributesSHGFI_ICONLOCATION = 0x000001000, // get icon locationSHGFI_EXETYPE = 0x000002000, // return exe typeSHGFI_SYSICONINDEX = 0x000004000, // get system icon indexSHGFI_LINKOVERLAY = 0x000008000, // put a link overlay on iconSHGFI_SELECTED = 0x000010000, // show icon in selected stateSHGFI_ATTR_SPECIFIED = 0x000020000, // get only specified attributesSHGFI_LARGEICON = 0x000000000, // get large iconSHGFI_SMALLICON = 0x000000001, // get small iconSHGFI_OPENICON = 0x000000002, // get open iconSHGFI_SHELLICONSIZE = 0x000000004, // get shell size iconSHGFI_PIDL = 0x000000008, // pszPath is a pidlSHGFI_USEFILEATTRIBUTES = 0x000000010, // use passed dwFileAttributeSHGFI_ADDOVERLAYS = 0x000000020, // apply the appropriate overlaysSHGFI_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);elsehI = 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;}}} 
