c# - 如何根据扩展名获取文件类型信息？ (不是 MIME)在 c# 中

Question

如何像 Explorer 那样获取基于扩展名的一般文件类型描述？所以不是 MIME，而是最终用户看到的信息，例如。

.doc = Microsoft Office Word 97 - 2003 文档.zip = 压缩文件.avi = 视频文件。

我怎样才能获得似乎可用的“次要”信息，我猜它不是基于扩展的。就像在“视频文件”上一样，它可以为您提供电影的“长度”或在文档文件上它有多少页......等等......

Answer 1

谢谢 Dan，好的。这回答了我的第一个问题。可惜不是第二个。注意:并非所有内容都打印出来。归功于 PInvoke.net

using System;
using System.Runtime.InteropServices;
using System.Text;
using System.Diagnostics;


namespace WindowsFormsApplication1
{
    static class Program
    {
        [DllImport("Shlwapi.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern uint AssocQueryString(AssocF flags, AssocStr str, string pszAssoc, string pszExtra, [Out] StringBuilder pszOut, [In][Out] ref uint pcchOut);

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Debug.WriteLine(FileExtentionInfo(AssocStr.Command, ".doc"), "Command");
            Debug.WriteLine(FileExtentionInfo(AssocStr.DDEApplication, ".doc"), "DDEApplication");
            Debug.WriteLine(FileExtentionInfo(AssocStr.DDEIfExec, ".doc"), "DDEIfExec");
            Debug.WriteLine(FileExtentionInfo(AssocStr.DDETopic, ".doc"), "DDETopic");
            Debug.WriteLine(FileExtentionInfo(AssocStr.Executable, ".doc"), "Executable");
            Debug.WriteLine(FileExtentionInfo(AssocStr.FriendlyAppName, ".doc"), "FriendlyAppName");
            Debug.WriteLine(FileExtentionInfo(AssocStr.FriendlyDocName, ".doc"), "FriendlyDocName");
            Debug.WriteLine(FileExtentionInfo(AssocStr.NoOpen, ".doc"), "NoOpen");
            Debug.WriteLine(FileExtentionInfo(AssocStr.ShellNewValue, ".doc"), "ShellNewValue");

            //  DDEApplication: WinWord
            //DDEIfExec: Ñﻴ߾
            //  DDETopic: System
            //  Executable: C:\Program Files (x86)\Microsoft Office\Office12\WINWORD.EXE
            //  FriendlyAppName: Microsoft Office Word
            //  FriendlyDocName: Microsoft Office Word 97 - 2003 Document


        }

        public static string FileExtentionInfo(AssocStr assocStr, string doctype)
        {
            uint pcchOut = 0;
            AssocQueryString(AssocF.Verify, assocStr, doctype, null, null, ref pcchOut);

            StringBuilder pszOut = new StringBuilder((int)pcchOut);
            AssocQueryString(AssocF.Verify, assocStr, doctype, null, pszOut, ref pcchOut);
            return pszOut.ToString();
        }

        [Flags]
        public enum AssocF
        {
            Init_NoRemapCLSID = 0x1,
            Init_ByExeName = 0x2,
            Open_ByExeName = 0x2,
            Init_DefaultToStar = 0x4,
            Init_DefaultToFolder = 0x8,
            NoUserSettings = 0x10,
            NoTruncate = 0x20,
            Verify = 0x40,
            RemapRunDll = 0x80,
            NoFixUps = 0x100,
            IgnoreBaseClass = 0x200
        }

        public enum AssocStr
        {
            Command = 1,
            Executable,
            FriendlyDocName,
            FriendlyAppName,
            NoOpen,
            ShellNewValue,
            DDECommand,
            DDEIfExec,
            DDEApplication,
            DDETopic
        }

    }
}