我知道可以使用以下方法提取文件的图标:
using (System.Drawing.Icon sysicon = System.Drawing.Icon.ExtractAssociatedIcon(filePath))
{
icon = System.Windows.Interop.Imaging.CreateBitmapSourceFromHIcon(
sysicon.Handle,
System.Windows.Int32Rect.Empty,
System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());
}
但是如果没有文件，我如何获取特定扩展名的图标呢？
使用这篇来自Paul Ingles的CodeProject文章中的GetFileIcon方法，并将.ext作为name参数传递。
GetFileIcon方法是对本地SHGetFileInfo的包装器，这里进行演示：
public static System.Drawing.Icon GetFileIcon(string name, IconSize size,
bool linkOverlay)
{
Shell32.SHFILEINFO shfi = new Shell32.SHFILEINFO();
uint flags = Shell32.SHGFI_ICON | Shell32.SHGFI_USEFILEATTRIBUTES;
if (true == linkOverlay) flags += Shell32.SHGFI_LINKOVERLAY;
/* Check the size specified for return. */
if (IconSize.Small == size)
{
flags += Shell32.SHGFI_SMALLICON ; // include the small icon flag
}
else
{
flags += Shell32.SHGFI_LARGEICON ; // include the large icon flag
}
Shell32.SHGetFileInfo( name,
Shell32.FILE_ATTRIBUTE_NORMAL,
ref shfi,
(uint) System.Runtime.InteropServices.Marshal.SizeOf(shfi),
flags );
// Copy (clone) the returned icon to a new object, thus allowing us
// to call DestroyIcon immediately
System.Drawing.Icon icon = (System.Drawing.Icon)
System.Drawing.Icon.FromHandle(shfi.hIcon).Clone();
User32.DestroyIcon( shfi.hIcon ); // Cleanup
return icon;
}
以下代码也基于Paul Ingles的解决方案，但是：
ImageSource而不是Icon)我在Windows 7和Windows XP SP3上进行了测试，它可以正常工作并接受任何字符串作为fileName。
using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Media.Imaging;
/// <summary>
/// Internals are mostly from here: http://www.codeproject.com/Articles/2532/Obtaining-and-managing-file-and-folder-icons-using
/// Caches all results.
/// </summary>
public static class IconManager
{
private static readonly Dictionary<string, ImageSource> _smallIconCache = new Dictionary<string, ImageSource>();
private static readonly Dictionary<string, ImageSource> _largeIconCache = new Dictionary<string, ImageSource>();
/// <summary>
/// Get an icon for a given filename
/// </summary>
/// <param name="fileName">any filename</param>
/// <param name="large">16x16 or 32x32 icon</param>
/// <returns>null if path is null, otherwise - an icon</returns>
public static ImageSource FindIconForFilename(string fileName, bool large)
{
var extension = Path.GetExtension(fileName);
if (extension == null)
return null;
var cache = large ? _largeIconCache : _smallIconCache;
ImageSource icon;
if (cache.TryGetValue(extension, out icon))
return icon;
icon = IconReader.GetFileIcon(fileName, large ? IconReader.IconSize.Large : IconReader.IconSize.Small, false).ToImageSource();
cache.Add(extension, icon);
return icon;
}
/// <summary>
/// https://dev59.com/6XNA5IYBdhLWcg3wAI3e#6580799
/// </summary>
static ImageSource ToImageSource(this Icon icon)
{
var imageSource = Imaging.CreateBitmapSourceFromHIcon(
icon.Handle,
Int32Rect.Empty,
BitmapSizeOptions.FromEmptyOptions());
return imageSource;
}
/// <summary>
/// Provides static methods to read system icons for both folders and files.
/// </summary>
/// <example>
/// <code>IconReader.GetFileIcon("c:\\general.xls");</code>
/// </example>
static class IconReader
{
/// <summary>
/// Options to specify the size of icons to return.
/// </summary>
public enum IconSize
{
/// <summary>
/// Specify large icon - 32 pixels by 32 pixels.
/// </summary>
Large = 0,
/// <summary>
/// Specify small icon - 16 pixels by 16 pixels.
/// </summary>
Small = 1
}
/// <summary>
/// Returns an icon for a given file - indicated by the name parameter.
/// </summary>
/// <param name="name">Pathname for file.</param>
/// <param name="size">Large or small</param>
/// <param name="linkOverlay">Whether to include the link icon</param>
/// <returns>System.Drawing.Icon</returns>
public static Icon GetFileIcon(string name, IconSize size, bool linkOverlay)
{
var shfi = new Shell32.Shfileinfo();
var flags = Shell32.ShgfiIcon | Shell32.ShgfiUsefileattributes;
if (linkOverlay) flags += Shell32.ShgfiLinkoverlay;
/* Check the size specified for return. */
if (IconSize.Small == size)
flags += Shell32.ShgfiSmallicon;
else
flags += Shell32.ShgfiLargeicon;
Shell32.SHGetFileInfo(name,
Shell32.FileAttributeNormal,
ref shfi,
(uint)Marshal.SizeOf(shfi),
flags);
// Copy (clone) the returned icon to a new object, thus allowing us to clean-up properly
var icon = (Icon)Icon.FromHandle(shfi.hIcon).Clone();
User32.DestroyIcon(shfi.hIcon); // Cleanup
return icon;
}
}
/// <summary>
/// Wraps necessary Shell32.dll structures and functions required to retrieve Icon Handles using SHGetFileInfo. Code
/// courtesy of MSDN Cold Rooster Consulting case study.
/// </summary>
static class Shell32
{
private const int MaxPath = 256;
[StructLayout(LayoutKind.Sequential)]
public struct Shfileinfo
{
private const int Namesize = 80;
public readonly IntPtr hIcon;
private readonly int iIcon;
private readonly uint dwAttributes;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = MaxPath)]
private readonly string szDisplayName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = Namesize)]
private readonly string szTypeName;
};
public const uint ShgfiIcon = 0x000000100; // get icon
public const uint ShgfiLinkoverlay = 0x000008000; // put a link overlay on icon
public const uint ShgfiLargeicon = 0x000000000; // get large icon
public const uint ShgfiSmallicon = 0x000000001; // get small icon
public const uint ShgfiUsefileattributes = 0x000000010; // use passed dwFileAttribute
public const uint FileAttributeNormal = 0x00000080;
[DllImport("Shell32.dll")]
public static extern IntPtr SHGetFileInfo(
string pszPath,
uint dwFileAttributes,
ref Shfileinfo psfi,
uint cbFileInfo,
uint uFlags
);
}
/// <summary>
/// Wraps necessary functions imported from User32.dll. Code courtesy of MSDN Cold Rooster Consulting example.
/// </summary>
static class User32
{
/// <summary>
/// Provides access to function required to delete handle. This method is used internally
/// and is not required to be called separately.
/// </summary>
/// <param name="hIcon">Pointer to icon handle.</param>
/// <returns>N/A</returns>
[DllImport("User32.dll")]
public static extern int DestroyIcon(IntPtr hIcon);
}
}
这件事可以更简单地完成：
System.Drawing.Icon.ExtractAssociatedIcon("<fullPath>");
重要提示：如果文件不存在，则会抛出一个异常，因此值得添加验证。
Icon.ExtractAssociatedIcon(@"c:\temp\this_is_actually_a_text_file.xls"); 将返回正确的 Excel 图标，即使该文件只是一个文本文件。 - stuartd像@astef一样，我也需要在WPF中使用它，但是我确实需要文件夹的图标。 由于驱动器和文件夹没有扩展名，因此我使用DirectoryInfo来确定哪一个是哪一个。
对于文件夹，我始终使用其关闭的图标，但是您可以轻松地将其扩展到考虑打开或关闭。
/// <summary>
/// Internals are mostly from here: http://www.codeproject.com/Articles/2532/Obtaining-and-managing-file-and-folder-icons-using
/// Caches all results.
/// </summary>
public static class IconManager
{
private static readonly Dictionary<string, ImageSource> _smallIconCache = new Dictionary<string, ImageSource>();
private static readonly Dictionary<string, ImageSource> _largeIconCache = new Dictionary<string, ImageSource>();
/// <summary>
/// Get an icon for a given filename
/// </summary>
/// <param name="fileName">any filename</param>
/// <param name="large">16x16 or 32x32 icon</param>
/// <returns>null if path is null, otherwise - an icon</returns>
public static ImageSource FindIconForFilename(string fileName, bool large)
{
DirectoryInfo di = new DirectoryInfo(fileName);
string extension = di.Extension;
if (extension == null)
return null;
if (extension == string.Empty && di.Root.FullName == di.FullName) {
extension = "ROOT";
}
if (extension == string.Empty && di.Attributes.HasFlag(FileAttributes.Directory)) {
extension = "FOLDER";
} else {
if (di.Attributes.HasFlag(FileAttributes.Directory) && extension != "ROOT") {
extension = "FOLDER";
}
}
var cache = large ? _largeIconCache : _smallIconCache;
ImageSource icon;
if (cache.TryGetValue(extension, out icon))
return icon;
if (di.Attributes.HasFlag(FileAttributes.Directory) && extension != "ROOT") {
icon = IconReader.GetFolderIcon(fileName, large ? IconReader.IconSize.Large : IconReader.IconSize.Small, IconReader.FolderType.Closed).ToImageSource();
} else {
icon = IconReader.GetFileIcon(fileName, large ? IconReader.IconSize.Large : IconReader.IconSize.Small, false).ToImageSource();
}
if (extension != "ROOT") cache.Add(extension, icon);
return icon;
}
/// <summary>
/// https://dev59.com/6XNA5IYBdhLWcg3wAI3e#6580799
/// </summary>
static ImageSource ToImageSource(this System.Drawing.Icon icon)
{
var imageSource = Imaging.CreateBitmapSourceFromHIcon(
icon.Handle,
Int32Rect.Empty,
BitmapSizeOptions.FromEmptyOptions());
return imageSource;
}
/// <summary>
/// Provides static methods to read system icons for both folders and files.
/// </summary>
/// <example>
/// <code>IconReader.GetFileIcon("c:\\general.xls");</code>
/// </example>
static class IconReader
{
/// <summary>
/// Options to specify the size of icons to return.
/// </summary>
public enum IconSize
{
/// <summary>
/// Specify large icon - 32 pixels by 32 pixels.
/// </summary>
Large = 0,
/// <summary>
/// Specify small icon - 16 pixels by 16 pixels.
/// </summary>
Small = 1
}
/// <summary>
/// Returns an icon for a given file - indicated by the name parameter.
/// </summary>
/// <param name="name">Pathname for file.</param>
/// <param name="size">Large or small</param>
/// <param name="linkOverlay">Whether to include the link icon</param>
/// <returns>System.Drawing.Icon</returns>
public static System.Drawing.Icon GetFileIcon(string name, IconSize size, bool linkOverlay)
{
var shfi = new Shell32.SHFILEINFO();
var flags = Shell32.SHGFI_ICON;
if (linkOverlay) flags += Shell32.SHGFI_LINKOVERLAY;
/* Check the size specified for return. */
if (IconSize.Small == size)
flags += Shell32.SHGFI_SMALLICON;
else
flags += Shell32.SHGFI_SMALLICON;
Shell32.SHGetFileInfo(name,
Shell32.FILE_ATTRIBUTE_NORMAL,
ref shfi,
(uint)Marshal.SizeOf(shfi),
flags);
// Copy (clone) the returned icon to a new object, thus allowing us to clean-up properly
var icon = (System.Drawing.Icon)System.Drawing.Icon.FromHandle(shfi.hIcon).Clone();
User32.DestroyIcon(shfi.hIcon); // Cleanup
return icon;
}
/// <summary>
/// Options to specify whether folders should be in the open or closed state.
/// </summary>
public enum FolderType
{
/// <summary>
/// Specify open folder.
/// </summary>
Open = 0,
/// <summary>
/// Specify closed folder.
/// </summary>
Closed = 1
}
/// <summary>
/// Used to access system folder icons.
/// </summary>
/// <param name="size">Specify large or small icons.</param>
/// <param name="folderType">Specify open or closed FolderType.</param>
/// <returns>System.Drawing.Icon</returns>
public static System.Drawing.Icon GetFolderIcon(string name, IconSize size, FolderType folderType)
{
// Need to add size check, although errors generated at present!
uint flags = Shell32.SHGFI_ICON | Shell32.SHGFI_SYSICONINDEX;
if (FolderType.Open == folderType) {
flags += Shell32.SHGFI_OPENICON;
}
if (IconSize.Small == size) {
flags += Shell32.SHGFI_SMALLICON;
} else {
flags += Shell32.SHGFI_LARGEICON;
}
// Get the folder icon
Shell32.SHFILEINFO shfi = new Shell32.SHFILEINFO();
Shell32.SHGetFileInfo(name,
Shell32.FILE_ATTRIBUTE_DIRECTORY,
ref shfi,
(uint)System.Runtime.InteropServices.Marshal.SizeOf(shfi),
flags);
System.Drawing.Icon.FromHandle(shfi.hIcon); // Load the icon from an HICON handle
// Now clone the icon, so that it can be successfully stored in an ImageList
System.Drawing.Icon icon = (System.Drawing.Icon)System.Drawing.Icon.FromHandle(shfi.hIcon).Clone();
User32.DestroyIcon(shfi.hIcon); // Cleanup
return icon;
}
}
}
/// <summary>
/// Wraps necessary Shell32.dll structures and functions required to retrieve Icon Handles using SHGetFileInfo. Code
/// courtesy of MSDN Cold Rooster Consulting case study.
/// </summary>
public class Shell32
{
public const int MAX_PATH = 256;
[StructLayout(LayoutKind.Sequential)]
public struct SHITEMID
{
public ushort cb;
[MarshalAs(UnmanagedType.LPArray)]
public byte[] abID;
}
[StructLayout(LayoutKind.Sequential)]
public struct ITEMIDLIST
{
public SHITEMID mkid;
}
[StructLayout(LayoutKind.Sequential)]
public struct BROWSEINFO
{
public IntPtr hwndOwner;
public IntPtr pidlRoot;
public IntPtr pszDisplayName;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpszTitle;
public uint ulFlags;
public IntPtr lpfn;
public int lParam;
public IntPtr iImage;
}
// Browsing for directory.
public const uint BIF_RETURNONLYFSDIRS = 0x0001;
public const uint BIF_DONTGOBELOWDOMAIN = 0x0002;
public const uint BIF_STATUSTEXT = 0x0004;
public const uint BIF_RETURNFSANCESTORS = 0x0008;
public const uint BIF_EDITBOX = 0x0010;
public const uint BIF_VALIDATE = 0x0020;
public const uint BIF_NEWDIALOGSTYLE = 0x0040;
public const uint BIF_USENEWUI = (BIF_NEWDIALOGSTYLE | BIF_EDITBOX);
public const uint BIF_BROWSEINCLUDEURLS = 0x0080;
public const uint BIF_BROWSEFORCOMPUTER = 0x1000;
public const uint BIF_BROWSEFORPRINTER = 0x2000;
public const uint BIF_BROWSEINCLUDEFILES = 0x4000;
public const uint BIF_SHAREABLE = 0x8000;
[StructLayout(LayoutKind.Sequential)]
public struct SHFILEINFO
{
public const int NAMESIZE = 80;
public IntPtr hIcon;
public int iIcon;
public uint dwAttributes;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_PATH)]
public string szDisplayName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = NAMESIZE)]
public string szTypeName;
};
public const uint SHGFI_ICON = 0x000000100; // get icon
public const uint SHGFI_DISPLAYNAME = 0x000000200; // get display name
public const uint SHGFI_TYPENAME = 0x000000400; // get type name
public const uint SHGFI_ATTRIBUTES = 0x000000800; // get attributes
public const uint SHGFI_ICONLOCATION = 0x000001000; // get icon location
public const uint SHGFI_EXETYPE = 0x000002000; // return exe type
public const uint SHGFI_SYSICONINDEX = 0x000004000; // get system icon index
public const uint SHGFI_LINKOVERLAY = 0x000008000; // put a link overlay on icon
public const uint SHGFI_SELECTED = 0x000010000; // show icon in selected state
public const uint SHGFI_ATTR_SPECIFIED = 0x000020000; // get only specified attributes
public const uint SHGFI_LARGEICON = 0x000000000; // get large icon
public const uint SHGFI_SMALLICON = 0x000000001; // get small icon
public const uint SHGFI_OPENICON = 0x000000002; // get open icon
public const uint SHGFI_SHELLICONSIZE = 0x000000004; // get shell size icon
public const uint SHGFI_PIDL = 0x000000008; // pszPath is a pidl
public const uint SHGFI_USEFILEATTRIBUTES = 0x000000010; // use passed dwFileAttribute
public const uint SHGFI_ADDOVERLAYS = 0x000000020; // apply the appropriate overlays
public const uint SHGFI_OVERLAYINDEX = 0x000000040; // Get the index of the overlay
public const uint FILE_ATTRIBUTE_DIRECTORY = 0x00000010;
public const uint FILE_ATTRIBUTE_NORMAL = 0x00000080;
[DllImport("Shell32.dll")]
public static extern IntPtr SHGetFileInfo(
string pszPath,
uint dwFileAttributes,
ref SHFILEINFO psfi,
uint cbFileInfo,
uint uFlags
);
}
/// <summary>
/// Wraps necessary functions imported from User32.dll. Code courtesy of MSDN Cold Rooster Consulting example.
/// </summary>
static class User32
{
/// <summary>
/// Provides access to function required to delete handle. This method is used internally
/// and is not required to be called separately.
/// </summary>
/// <param name="hIcon">Pointer to icon handle.</param>
/// <returns>N/A</returns>
[DllImport("User32.dll")]
public static extern int DestroyIcon(IntPtr hIcon);
}
}