public static ImageSource GetIcon(string fileName)
{
    Icon icon = Icon.ExtractAssociatedIcon(fileName);
    return System.Windows.Interop.Imaging.CreateBitmapSourceFromHIcon(
                icon.Handle,new Int32Rect(icon.Width,icon.Height),BitmapSizeOptions.FromEmptyOptions());
}

另一个选项,如果不想使用System.Drawing,则是从SHGetFileInfo API获取图标.更困难,也更灵活;例如,您可以根据扩展名获得不存在的文件的图标(当然,对于可执行文件,它不是非常有用,因为它将返回可执行文件的默认图标).

public static ImageSource GetIcon(string path,bool smallIcon,bool isDirectory)
{
    // SHGFI_USEFILEATTRIBUTES takes the file name and attributes into account if it doesn't exist
    uint flags = SHGFI_ICON | SHGFI_USEFILEATTRIBUTES;
    if (smallIcon)
        flags |= SHGFI_SMALLICON;

    uint attributes = FILE_ATTRIBUTE_NORMAL;
    if (isDirectory)
        attributes |= FILE_ATTRIBUTE_DIRECTORY;

    SHFILEINFO shfi;
    if (0 != SHGetFileInfo(
                path,attributes,out shfi,(uint)Marshal.SizeOf(typeof(SHFILEINFO)),flags))
    {
        return System.Windows.Interop.Imaging.CreateBitmapSourceFromHIcon(
                    shfi.hIcon,Int32Rect.Empty,BitmapSizeOptions.FromEmptyOptions());
    }
    return null;
}

[StructLayout(LayoutKind.Sequential)]
private 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")]
    private static extern int SHGetFileInfo(string pszPath,uint dwFileAttributes,out SHFILEINFO psfi,uint cbFileInfo,uint flags);

private const uint FILE_ATTRIBUTE_READONLY = 0x00000001;
private const uint FILE_ATTRIBUTE_HIDDEN = 0x00000002;
private const uint FILE_ATTRIBUTE_SYSTEM = 0x00000004;
private const uint FILE_ATTRIBUTE_DIRECTORY = 0x00000010;
private const uint FILE_ATTRIBUTE_ARCHIVE = 0x00000020;
private const uint FILE_ATTRIBUTE_DEVICE = 0x00000040;
private const uint FILE_ATTRIBUTE_NORMAL = 0x00000080;
private const uint FILE_ATTRIBUTE_TEMPORARY = 0x00000100;
private const uint FILE_ATTRIBUTE_SPARSE_FILE = 0x00000200;
private const uint FILE_ATTRIBUTE_REPARSE_POINT = 0x00000400;
private const uint FILE_ATTRIBUTE_COMPRESSED = 0x00000800;
private const uint FILE_ATTRIBUTE_OFFLINE = 0x00001000;
private const uint FILE_ATTRIBUTE_NOT_CONTENT_INDEXED = 0x00002000;
private const uint FILE_ATTRIBUTE_ENCRYPTED = 0x00004000;
private const uint FILE_ATTRIBUTE_VIRTUAL = 0x00010000;

private const uint SHGFI_ICON = 0x000000100;     // get icon
private const uint SHGFI_DISPLAYNAME = 0x000000200;     // get display name
private const uint SHGFI_TYPENAME = 0x000000400;     // get type name
private const uint SHGFI_ATTRIBUTES = 0x000000800;     // get attributes
private const uint SHGFI_ICONLOCATION = 0x000001000;     // get icon location
private const uint SHGFI_EXETYPE = 0x000002000;     // return exe type
private const uint SHGFI_SYSICONINDEX = 0x000004000;     // get system icon index
private const uint SHGFI_LINKOVERLAY = 0x000008000;     // put a link overlay on icon
private const uint SHGFI_SELECTED = 0x000010000;     // show icon in selected state
private const uint SHGFI_ATTR_SPECIFIED = 0x000020000;     // get only specified attributes
private const uint SHGFI_LARGEICON = 0x000000000;     // get large icon
private const uint SHGFI_SMALLICON = 0x000000001;     // get small icon
private const uint SHGFI_OPENICON = 0x000000002;     // get open icon
private const uint SHGFI_SHELLICONSIZE = 0x000000004;     // get shell size icon
private const uint SHGFI_PIDL = 0x000000008;     // pszPath is a pidl
private const uint SHGFI_USEFILEATTRIBUTES = 0x000000010;     // use passed dwFileAttribute

这种方法的另一个优点是它还可以获取目录的图标(请参阅代码中的上一编辑),这不可能与Icon.ExtractAssociatedIcon