如何：獲取有關文件、文件夾和驅動器的信息（C# 編程指南） · MSDN C# 編程指南 & 參考手冊 2015

# 如何：獲取有關文件、文件夾和驅動器的信息（C# 編程指南）在 .NET Framework 中，可以使用以下類來訪問文件系統信息： * [System.IO.FileInfo](https://msdn.microsoft.com/zh-cn/library/system.io.fileinfo.aspx) * [System.IO.DirectoryInfo](https://msdn.microsoft.com/zh-cn/library/system.io.directoryinfo.aspx) * [System.IO.DriveInfo](https://msdn.microsoft.com/zh-cn/library/system.io.driveinfo.aspx) * [System.IO.Directory](https://msdn.microsoft.com/zh-cn/library/system.io.directory.aspx) * [System.IO.File](https://msdn.microsoft.com/zh-cn/library/system.io.file.aspx) [FileInfo](https://msdn.microsoft.com/zh-cn/library/system.io.fileinfo.aspx) 和 [DirectoryInfo](https://msdn.microsoft.com/zh-cn/library/system.io.directoryinfo.aspx) 類表示文件或目錄，包含公開 NTFS 文件系統所支持的很多文件特性的屬性，同時還包含用于打開、關閉、移動和刪除文件和文件夾的方法。可以通過將表示文件、文件夾或驅動器名稱的字符串傳遞到下面的構造函數來創建這些類的實例： ``` System.IO.DriveInfo di = new System.IO.DriveInfo(@"C:\"); ``` 此外，還可以通過調用 [DirectoryInfo.GetDirectories](https://msdn.microsoft.com/zh-cn/library/s7xk2b58.aspx)、[DirectoryInfo.GetFiles](https://msdn.microsoft.com/zh-cn/library/4cyf24ss.aspx) 和 [DriveInfo.RootDirectory](https://msdn.microsoft.com/zh-cn/library/system.io.driveinfo.rootdirectory.aspx) 來獲取文件、文件夾或驅動器的名稱。 [System.IO.Directory](https://msdn.microsoft.com/zh-cn/library/system.io.directory.aspx) 和 [System.IO.File](https://msdn.microsoft.com/zh-cn/library/system.io.file.aspx) 類提供用于檢索有關目錄和文件的信息的靜態方法。下面的示例演示訪問有關文件和文件夾的信息的各種方法。 ``` class FileSysInfo { static void Main() { // You can also use System.Environment.GetLogicalDrives to // obtain names of all logical drives on the computer. System.IO.DriveInfo di = new System.IO.DriveInfo(@"C:\"); Console.WriteLine(di.TotalFreeSpace); Console.WriteLine(di.VolumeLabel); // Get the root directory and print out some information about it. System.IO.DirectoryInfo dirInfo = di.RootDirectory; Console.WriteLine(dirInfo.Attributes.ToString()); // Get the files in the directory and print out some information about them. System.IO.FileInfo[] fileNames = dirInfo.GetFiles("*.*"); foreach (System.IO.FileInfo fi in fileNames) { Console.WriteLine("{0}: {1}: {2}", fi.Name, fi.LastAccessTime, fi.Length); } // Get the subdirectories directly that is under the root. // See "How to: Iterate Through a Directory Tree" for an example of how to // iterate through an entire tree. System.IO.DirectoryInfo[] dirInfos = dirInfo.GetDirectories("*.*"); foreach (System.IO.DirectoryInfo d in dirInfos) { Console.WriteLine(d.Name); } // The Directory and File classes provide several static methods // for accessing files and directories. // Get the current application directory. string currentDirName = System.IO.Directory.GetCurrentDirectory(); Console.WriteLine(currentDirName); // Get an array of file names as strings rather than FileInfo objects. // Use this method when storage space is an issue, and when you might // hold on to the file name reference for a while before you try to access // the file. string[] files = System.IO.Directory.GetFiles(currentDirName, "*.txt"); foreach (string s in files) { // Create the FileInfo object only when needed to ensure // the information is as current as possible. System.IO.FileInfo fi = null; try { fi = new System.IO.FileInfo(s); } catch (System.IO.FileNotFoundException e) { // To inform the user and continue is // sufficient for this demonstration. // Your application may require different behavior. Console.WriteLine(e.Message); continue; } Console.WriteLine("{0} : {1}",fi.Name, fi.Directory); } // Change the directory. In this case, first check to see // whether it already exists, and create it if it does not. // If this is not appropriate for your application, you can // handle the System.IO.IOException that will be raised if the // directory cannot be found. if (!System.IO.Directory.Exists(@"C:\Users\Public\TestFolder\")) { System.IO.Directory.CreateDirectory(@"C:\Users\Public\TestFolder\"); } System.IO.Directory.SetCurrentDirectory(@"C:\Users\Public\TestFolder\"); currentDirName = System.IO.Directory.GetCurrentDirectory(); Console.WriteLine(currentDirName); // Keep the console window open in debug mode. Console.WriteLine("Press any key to exit."); Console.ReadKey(); } } ``` ## 可靠編程處理用戶指定的路徑字符串時，還應處理在以下情況下引發的異常： * 文件名的格式不正確。例如，包含無效字符或僅包含空白。 * 文件名為空。 * 文件名長于系統定義的最大長度。 * 文件名包含冒號 (:)。如果應用程序不具有讀取指定文件所需的足夠權限，則無論路徑是否存在，**Exists** 方法都將返回 **false**；該方法不引發異常。 ## 請參閱 [System.IO](https://msdn.microsoft.com/zh-cn/library/system.io.aspx) [C# 編程指南](https://msdn.microsoft.com/zh-cn/library/67ef8sbd.aspx) [文件系統和注冊表（C# 編程指南）](https://msdn.microsoft.com/zh-cn/library/2kzb96fk.aspx)