using?System;
using?System.IO;
using?System.Drawing;
using?Microsoft.Win32;
using?System.Runtime.InteropServices;


namespace?GetIconDemo
{
??///?<summary>
??///?提供從操作系統讀取圖標的方法
??///?</summary>
??public?class?GetSystemIcon
??{
????///?<summary>
????///?依據文件名讀取圖標，若指定文件不存在，則返回空值。
????///?</summary>
????///?<param?name="fileName"></param>
????///?<returns></returns>
????public?static?Icon?GetIconByFileName(string?fileName)
????{
????????if?(fileName?==?null?||?fileName.Equals(string.Empty))?return?null;
????????if?(!File.Exists(fileName))?return?null;

????????SHFILEINFO?shinfo?=?new?SHFILEINFO();
????????//Use?this?to?get?the?small?Icon
????????Win32.SHGetFileInfo(fileName,?0,?ref?shinfo,?(uint)Marshal.SizeOf(shinfo),?Win32.SHGFI_ICON?|?Win32.SHGFI_SMALLICON);
????????//The?icon?is?returned?in?the?hIcon?member?of?the?shinfo?struct
????????System.Drawing.Icon?myIcon?=?System.Drawing.Icon.FromHandle(shinfo.hIcon);
????????return?myIcon;
????}

????///?<summary>
????///?給出文件擴展名（.*），返回相應圖標
????///?若不以"."開頭則返回文件夾的圖標。
????///?</summary>
????///?<param?name="fileType"></param>
????///?<param?name="isLarge"></param>
????///?<returns></returns>
????public?static?Icon?GetIconByFileType(string?fileType,?bool?isLarge)
????{
????????if?(fileType?==?null?||?fileType.Equals(string.Empty))?return?null;

????????RegistryKey?regVersion?=?null;
????????string?regFileType?=?null;
????????string?regIconString?=?null;
????????string?systemDirectory?=?Environment.SystemDirectory?+?"\\";

????????if?(fileType[0]?==?'.')
????????{
??????????//讀系統注冊表中文件類型信息
??????????regVersion?=?Registry.ClassesRoot.OpenSubKey(fileType,?true);
??????????if?(regVersion?!=?null)
??????????{
????????????regFileType?=?regVersion.GetValue("")?as?string;
????????????regVersion.Close();
????????????regVersion?=?Registry.ClassesRoot.OpenSubKey(regFileType?+?@"\DefaultIcon",?true);
????????????if?(regVersion?!=?null)
????????????{
????????????????regIconString?=?regVersion.GetValue("")?as?string;
????????????????regVersion.Close();
????????????}
??????????}
??????????if?(regIconString?==?null)
??????????{
????????????//沒有讀取到文件類型注冊信息，指定為未知文件類型的圖標
????????????regIconString?=?systemDirectory?+?"shell32.dll,0";
??????????}
????????}
????????else
????????{
??????????//直接指定為文件夾圖標
??????????regIconString?=?systemDirectory?+?"shell32.dll,3";
????????}
????????string[]?fileIcon?=?regIconString.Split(new?char[]?{?','?});
????????if?(fileIcon.Length?!=?2)
????????{
??????????//系統注冊表中注冊的標圖不能直接提取，則返回可執行文件的通用圖標
??????????fileIcon?=?new?string[]?{?systemDirectory?+?"shell32.dll",?"2"?};
????????}
????????Icon?resultIcon?=?null;
????????try
????????{
??????????//調用API方法讀取圖標
??????????int[]?phiconLarge?=?new?int[1];
??????????int[]?phiconSmall?=?new?int[1];
??????????uint?count?=?Win32.ExtractIconEx(fileIcon[0],?Int32.Parse(fileIcon[1]),?phiconLarge,?phiconSmall,?1);
??????????IntPtr?IconHnd?=?new?IntPtr(isLarge???phiconLarge[0]?:?phiconSmall[0]);
??????????resultIcon?=?Icon.FromHandle(IconHnd);
????????}
????????catch?{?}
????????return?resultIcon;
????}
??}



??[StructLayout(LayoutKind.Sequential)]
??public?struct?SHFILEINFO
??{
????public?IntPtr?hIcon;
????public?IntPtr?iIcon;
????public?uint?dwAttributes;
????[MarshalAs(UnmanagedType.ByValTStr,?SizeConst?=?260)]
????public?string?szDisplayName;
????[MarshalAs(UnmanagedType.ByValTStr,?SizeConst?=?80)]
????public?string?szTypeName;
??};

??///?<summary>
??///?定義調用的API方法
??///?</summary>
??class?Win32
??{
????public?const?uint?SHGFI_ICON?=?0x100;
????public?const?uint?SHGFI_LARGEICON?=?0x0;?//?'Large?icon
????public?const?uint?SHGFI_SMALLICON?=?0x1;?//?'Small?icon

????[DllImport("shell32.dll")]
????public?static?extern?IntPtr?SHGetFileInfo(string?pszPath,?uint?dwFileAttributes,?ref?SHFILEINFO?psfi,?uint?cbSizeFileInfo,?uint?uFlags);
????[DllImport("shell32.dll")]
????public?static?extern?uint?ExtractIconEx(string?lpszFile,?int?nIconIndex,?int[]?phiconLarge,?int[]?phiconSmall,?uint?nIcons);

??}
}

實例
File Explorer.rar

轉載于:https://www.cnblogs.com/hun_dan/archive/2009/04/26/1443696.html

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