.Net Framework 4.0: Enumerating file system objects

核心提示：2009-10-27 20:07:44 | .net教程聚合 In my last posting I introduced new ReadLines() method and new overloads for WriteAllLines() method of File class. But there are

2009-10-27 20:07:44 | .net教程聚合
In my last posting I introduced new ReadLines() method and new overloads for WriteAllLines() method of File class. But there are more new stuff in System.IO namespace. In .Net Framework 4.0 Directory and DirectoryInfo class are able to enumerate files, directories and file system entries. In this posting I will show you these new features.

Let’s see now how to enumerate file system objects using new static methods of Directory class. There is one thing you should know. If you have to handle files and directories in same context then you should use EnumerateFileSystemEntries() method that enumerates both files and directories. The following example shows you how to enumerate different file system objects.


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static void Main(string[] args)

{

　　var path = Path.GetPathRoot(Environment.CurrentDirectory);



　　var files = Directory.EnumerateFiles(path);
　　var directories = Directory.EnumerateDirectories(path);　　
　　var entries = Directory.EnumerateFileSystemEntries(path);



　　Console.WriteLine("Files:");

　　foreach (var file in files)

　　　　Console.WriteLine(file);



　　Console.WriteLine("\r\nDirectories:");

　　foreach (var directory in directories)

　　　　Console.WriteLine(directory);



　　Console.WriteLine("\r\nEntries:");

　　foreach (var entry in entries)

　　　　Console.WriteLine(entry);



　　Console.ReadLine();

}


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You should get output like this (the path is root path of drive where application is located).

Files:
C:\autoexec.bat
C:\config.sys
C:\pagefile.sys
　Directories:
C:\$Recycle.BinC:\Documents and Settings
C:\Install
C:\PerfLogs　C:\PRogram Files
C:\ProgramData　C:\Recovery　C:\System Volume Information　C:\Users　C:\Windows
　Entries:
C:\$Recycle.Bin
C:\autoexec.bat
C:\config.sys
C:\Documents and Settings
C:\Install
C:\pagefile.sys
C:\PerfLogs
C:\Program Files
C:\ProgramData
C:\Recovery
C:\System Volume Information
C:\Users
C:\Windows
These enumerating methods work better than ones that return arrays because requests to file system are made only when concrete object is asked from enumerator. I think these methods may be very good load balancers in applications that make heavy use of file system.