文件操作工具类FileUtility（摘自UABv2.0）

王朝c#·作者佚名 2006-12-17

最近一直在研究 Smart Client 的 Smart Update 开发，从 Microsoft Updater Application Block v2.0 里面学到了很多东西，这里不得不佩服 Enterprise Library 的设计，设计模式和 XML 的运用使得 Enterprise Library 的扩展性很强，设计十分优美，是学习 OOP 的好范例。本人看了之后感叹自己写的代码大部分还是面向过程

。Enterprise Library 的广告就做到这里了，下面一个操作文件的工具类是从 Microsoft Updater Application Block v2.0 里面原封不动取出来，感觉具有一定的参考价值，希望对大家有帮助。//============================================================================================================// Microsoft Updater Application Block for .NET// http://msdn.microsoft.com/library/en-us/dnbda/html/updater.asp// // FileUtility.cs//// Contains the implementation of the FileUtility helper class.// // For more information see the Updater Application Block Implementation Overview. // //============================================================================================================// Copyright ?Microsoft Corporation. All rights reserved.// THIS CODE AND INFORMATION IS PROVIDED 'AS IS' WITHOUT WARRANTY// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND// FITNESS FOR A PARTICULAR PURPOSE.//============================================================================================================ using System;using System.IO;using System.Runtime.InteropServices; namespace Microsoft.ApplicationBlocks.Updater.Utilities{ /// <summary> /// Indicates how to proceed with the move file operation. /// </summary> [Flags] public enum MoveFileFlag : int { /// <summary> /// Perform a default move funtion. /// </summary> None = 0x00000000, /// <summary> /// If the target file exists, the move function will replace it. /// </summary> ReplaceExisting = 0x00000001, /// <summary> /// If the file is to be moved to a different volume, /// the function simulates the move by using the CopyFile and DeleteFile functions. /// </summary> CopyAllowed = 0x00000002, /// <summary> /// The system does not move the file until the operating system is restarted. /// The system moves the file immediately after AUTOCHK is executed, but before /// creating any paging files. Consequently, this parameter enables the function /// to delete paging files from previous startups. /// </summary> DelayUntilReboot = 0x00000004, /// <summary> /// The function does not return until the file has actually been moved on the disk. /// </summary> WriteThrough = 0x00000008, /// <summary> /// Reserved for future use. /// </summary> CreateHardLink = 0x00000010, /// <summary> /// The function fails if the source file is a link source, but the file cannot be tracked after the move. This situation can occur if the destination is a volume formatted with the FAT file system. /// </summary> FailIfNotTrackable = 0x00000020, } /// <summary> /// Provides certain utilities used by configuration processors, such as correcting file paths. /// </summary> public sealed class FileUtility { #region Constructor /// <summary> /// Default constructor. /// </summary> private FileUtility() { } #endregion #region Public members /// <summary> /// Returns whether the path is a UNC path. /// </summary> /// <param name='path'>The path string.</param> /// <returns><c>true</c> if the path is a UNC path.</returns> public static bool IsUncPath( string path ) { // FIRST, check if this is a URL or a UNC path; do this by attempting to construct uri object from it Uri url = new Uri( path ); if( url.IsUnc ) { // it is a unc path, return true return true; } else { return false; } } /// <summary> /// Takes a UNC or URL path, determines which it is (NOT hardened against bad strings, assumes one or the other is present) /// and returns the path with correct trailing slash: backslash for UNC or /// slash mark for URL. /// </summary> /// <param name='path'>The URL or UNC string.</param> /// <returns>Path with correct terminal slash.</returns> public static string AppendSlashUrlOrUnc( string path ) { if( IsUncPath( path ) ) { // it is a unc path, so decorate the end with a back-slash (to correct misconfigurations, defend against trivial errors) return AppendTerminalBackslash( path ); } else { // assume URL here return AppendTerminalForwardSlash( path ); } } /// <summary> /// If not present appends terminal backslash to paths. /// </summary> /// <param name='path'>A path string; for example, 'C:\AppUpdaterClient'.</param> /// <returns>A path string with trailing backslash; for example, 'C:\AppUpdaterClient\'.</returns> public static string AppendTerminalBackslash( string path ) { if( path.IndexOf( Path.DirectorySeparatorChar, path.Length - 1 ) == -1 ) { return path + Path.DirectorySeparatorChar; } else { return path; } } /// <summary> /// Appends a terminal slash mark if there is not already one; returns corrected path. /// </summary> /// <param name='path'>The path that may be missing a terminal slash mark.</param> /// <returns>The corrected path with terminal slash mark.</returns> public static string AppendTerminalForwardSlash( string path ) { if( path.IndexOf( Path.AltDirectorySeparatorChar, path.Length - 1 ) == -1 ) { return path + Path.AltDirectorySeparatorChar; } else { return path; } } /// <summary> /// Creates a new temporary folder under the system temp folder /// and returns its full pathname. /// </summary> /// <returns>The full temp path string.</returns> public static string CreateTemporaryFolder() { return Path.Combine( Path.GetTempPath(), Path.GetFileNameWithoutExtension( Path.GetTempFileName() ) ); } /// <summary> /// Copies files from the source to destination directories. Directory.Move is not /// suitable here because the downloader may still have the temporary /// directory locked. /// </summary> /// <param name='sourcePath'>The source path.</param> /// <param name='destinationPath'>The destination path.</param> public static void CopyDirectory( string sourcePath, string destinationPath ) { CopyDirectory( sourcePath, destinationPath, true ); } /// <summary> /// Copies files from the source to destination directories. Directory.Move is not /// suitable here because the downloader may still have the temporary /// directory locked. /// </summary> /// <param name='sourcePath'>The source path.</param> /// <param name='destinationPath'>The destination path.</param> /// <param name='overwrite'>Indicates whether the destination files should be overwritten.</param> public static void CopyDirectory( string sourcePath, string destinationPath, bool overwrite ) { CopyDirRecurse( sourcePath, destinationPath, destinationPath, overwrite ); } /// <summary> /// Move a file from a folder to a new one. /// </summary> /// <param name='existingFileName'>The original file name.</param> /// <param name='newFileName'>The new file name.</param> /// <param name='flags'>Flags about how to move the files.</param> /// <returns>indicates whether the file was moved.</returns> public static bool MoveFile( string existingFileName, string newFileName, MoveFileFlag flags) { return MoveFileEx( existingFileName, newFileName, (int)flags ); } /// <summary> /// Deletes a folder. If the folder cannot be deleted at the time this method is called, /// the deletion operation is delayed until the next system boot. /// </summary> /// <param name='folderPath'>The directory to be removed</param> public static void DestroyFolder( string folderPath ) { try { if ( Directory.Exists( folderPath) ) { Directory.Delete( folderPath, true ); } } catch( Exception ) { // If we couldn't remove the files, postpone it to the next system reboot if ( Directory.Exists( folderPath) ) { FileUtility.MoveFile( folderPath, null, MoveFileFlag.DelayUntilReboot ); } } } /// <summary> /// Deletes a file. If the file cannot be deleted at the time this method is called, /// the deletion operation is delayed until the next system boot. /// </summary> /// <param name='filePath'>The file to be removed</param> public static void DestroyFile( string filePath ) { try { if ( File.Exists( filePath ) ) { File.Delete( filePath ); } } catch { if ( File.Exists( filePath ) ) { FileUtility.MoveFile( filePath, null, MoveFileFlag.DelayUntilReboot ); } } } /// <summary> /// Returns the path to the newer version of the .NET Framework installed on the system. /// </summary> /// <returns>A string containig the full path to the newer .Net Framework location</returns> public static string GetLatestDotNetFrameworkPath() { Version latestVersion = null; string fwkPath = Path.GetFullPath( Path.Combine( Environment.SystemDirectory, @'..\Microsoft.NET\Framework' ) ); foreach(string path in Directory.GetDirectories( fwkPath, 'v*' ) ) { string candidateVersion = Path.GetFileName( path ).TrimStart( 'v' ); try { Version curVersion = new Version( candidateVersion ); if ( latestVersion == null || ( latestVersion != null && latestVersion < curVersion ) ) { latestVersion = curVersion; } } catch {} } return Path.Combine( fwkPath, 'v' + latestVersion.ToString() ); } #endregion #region Private members /// <summary> /// API declaration of the Win32 function. /// </summary> /// <param name='lpExistingFileName'>Existing file path.</param> /// <param name='lpNewFileName'>The file path.</param> /// <param name='dwFlags'>Move file flags.</param> /// <returns>Whether the file was moved or not.</returns> [DllImport('KERNEL32.DLL')] private static extern bool MoveFileEx( string lpExistingFileName, string lpNewFileName, long dwFlags ); /// <summary> /// Utility function that recursively copies directories and files. /// Again, we could use Directory.Move but we need to preserve the original. /// </summary> /// <param name='sourcePath'>The source path to copy.</param> /// <param name='destinationPath'>The destination path to copy to.</param> /// <param name='originalDestination'>The original dstination path.</param> /// <param name='overwrite'>Whether the folders should be copied recursively.</param> private static void CopyDirRecurse( string sourcePath, string destinationPath, string originalDestination, bool overwrite ) { // ensure terminal backslash sourcePath = FileUtility.AppendTerminalBackslash( sourcePath ); destinationPath = FileUtility.AppendTerminalBackslash( destinationPath ); if ( !Directory.Exists( destinationPath ) ) { Directory.CreateDirectory( destinationPath ); } // get dir info which may be file or dir info object DirectoryInfo dirInfo = new DirectoryInfo( sourcePath ); string destFileName = null; foreach( FileSystemInfo fsi in dirInfo.GetFileSystemInfos() ) { if ( fsi is FileInfo ) { destFileName = Path.Combine( destinationPath, fsi.Name ); // if file object just copy when overwrite is allowed if ( File.Exists( destFileName ) ) { if ( overwrite ) { File.Copy( fsi.FullName, destFileName, true ); } } else { File.Copy( fsi.FullName, destFileName ); } } else { // avoid this recursion path, otherwise copying directories as child directories // would be an endless recursion (up to an stack-overflow exception). if ( fsi.FullName != originalDestination ) { // must be a directory, create destination sub-folder and recurse to copy files //Directory.CreateDirectory( destinationPath + fsi.Name ); CopyDirRecurse( fsi.FullName, destinationPath + fsi.Name, originalDestination, overwrite ); } } } } #endregion }}