c# – 如何确定文件是否可执行？

[Flags]
internal enum SHGFI : uint
{
    ADDOVERLAYS = 0x20,ATTR_SPECIFIED = 0x20000,ATTRIBUTES = 0x800,DISPLAYNAME = 0x200,EXETYPE = 0x2000,ICON = 0x100,ICONLOCATION = 0x1000,LARGEICON = 0,LINKOVERLAY = 0x8000,OPENICON = 2,OVERLAYINDEX = 0x40,PIDL = 8,SELECTED = 0x10000,SHELLICONSIZE = 4,SMALLICON = 1,SYSICONINDEX = 0x4000,TYPENAME = 0x400,USEFILEATTRIBUTES = 0x10
}

/// <summary>
/// This structure contains information about a file object.
/// </summary>
/// <remarks>
/// This structure is used with the SHGetFileInfo function.
/// </remarks>
[StructLayout(LayoutKind.Sequential,CharSet = CharSet.Unicode)]
internal struct SHFILEINFO
{
    /// <summary>
    /// Handle to the icon that represents the file. 
    /// </summary>
    internal IntPtr hIcon;

    /// <summary>
    /// Index of the icon image within the system image list.
    /// </summary>
    internal int iIcon;

    /// <summary>
    /// Specifies the attributes of the file object.
    /// </summary>
    internal SFGAO dwAttributes;

    /// <summary>
    /// Null-terminated string that contains the name of the file as it 
    /// appears in the Windows shell,or the path and name of the file that
    /// contains the icon representing the file.
    /// </summary>
    [MarshalAs(UnmanagedType.ByValTStr,SizeConst = Constants.MAX_PATH)]
    internal string szDisplayName;

    /// <summary>
    /// Null-terminated string that describes the type of file. 
    /// </summary>
    [MarshalAs(UnmanagedType.ByValTStr,SizeConst = 80)]
    internal string szTypeName;        
}

/// <summary>
/// Specifies the executable file type.
/// </summary>
public enum ExecutableType : int
{
    /// <summary>
    /// The file executable type is not able to be determined.
    /// </summary>
    Unknown = 0,/// <summary>
    /// The file is an MS-DOS .exe,.com,or .bat file.
    /// </summary>
    DOS,/// <summary>
    /// The file is a Microsoft Win32?-based console application.
    /// </summary>
    Win32Console,/// <summary>
    /// The file is a Windows application.
    /// </summary>
    Windows,}

// Retrieves information about an object in the file system,// such as a file,a folder,a directory,or a drive root.
[DllImport("shell32",EntryPoint = "SHGetFileInfo",ExactSpelling = false,CharSet = CharSet.Auto,SetLastError = true)]
internal static extern IntPtr SHGetFileInfo(
    string pszPath,FileAttributes dwFileAttributes,ref SHFILEINFO sfi,int cbFileInfo,SHGFI uFlags);

[SecurityPermission(SecurityAction.LinkDemand,Flags = SecurityPermissionFlag.UnmanagedCode)]
private ExecutableType IsExecutable(string fileName)
{
    if (fileName == null)
    {
        throw new ArgumentNullException("fileName");
    }

    ExecutableType executableType = ExecutableType.Unknown;

    if (File.Exists(fileName)
    {
        // Try to fill the same SHFILEINFO struct for the exe type. The returned pointer contains the encoded 
        // executable type data.
        ptr = IntPtr.Zero;
        ptr = SHGetFileInfo(fileName,FileAttributes.Normal,ref this.shellFileInfo,Marshal.SizeOf(typeof(SHFILEINFO)),SHGFI.EXETYPE);

        // We need to split the returned pointer up into the high and low order words. These are important
        // because they help distinguish some of the types. The possible values are:
        //
        // Value                                            Meaning
        // ----------------------------------------------------------------------------------------------
        // 0                                                Nonexecutable file or an error condition. 
        // LOWORD = NE or PE and HIWORD = Windows version   Microsoft Windows application.
        // LOWORD = MZ and HIWORD = 0                       Windows 95,Windows 98: Microsoft MS-DOS .exe,or .bat file
        //                                                  Microsoft Windows NT,Windows 2000,Windows XP: MS-DOS .exe or .com file 
        // LOWORD = PE and HIWORD = 0                       Windows 95,Windows 98: Microsoft Win32 console application 
        //                                                  Windows NT,Windows XP: Win32 console application or .bat file 
        // MZ = 0x5A4D - DOS signature.
        // NE = 0x454E - OS/2 signature.
        // LE = 0x454C - OS/2 LE or VXD signature.
        // PE = 0x4550 - Win32/NT signature.

        int wparam = ptr.ToInt32();
        int loWord = wparam & 0xffff;
        int hiWord = wparam >> 16;

        if (wparam == 0)
        {
            executableType = ExecutableType.Unknown;
        }
        else
        {
            if (hiWord == 0x0000)
            {
                if (loWord == 0x5A4D)
                {
                    // The file is an MS-DOS .exe,or .bat
                    executableType = ExecutableType.DOS;
                }
                else if (loWord == 0x4550)
                {
                    executableType = ExecutableType.Win32Console;
                }
            }
            else
            {
                if (loWord == 0x454E || loWord == 0x4550)
                {
                    executableType = ExecutableType.Windows;
                }
                else if (loWord == 0x454C)
                {
                    executableType = ExecutableType.Windows;
                }
            }
        }
    }

    return executableType;
}

(这应该可行,但是从较大的库中提取,因此可能存在小问题.但是,它应该足够完整,以便在那里获得大部分内容.)