摘要：using System;using System.IO;class StreamProcessingExample{static void ProcessFiles(string directoryPath){foreach (var file in Dir
在 C# 中处理大规模文件和目录的遍历时，性能和内存问题是主要挑战。以下是优化的策略、技术和注意事项。
通过流式处理（Streaming）的方式逐步处理文件或目录，避免一次性加载全部数据。
using System;using System.IO;class StreamProcessingExample{static void ProcessFiles(string directoryPath){foreach (var file in Directory.EnumerateFiles(directoryPath, "*", SearchOption.AllDirectories)){Console.WriteLine(file); // 逐步处理每个文件}}static void Main{ProcessFiles("path/to/large/directory");}}通过并行处理加快文件和目录的遍历。
using System;using System.IO;using System.Linq;using System.Threading.Tasks;class ParallelProcessingExample{static void ProcessFiles(string directoryPath){var files = Directory.EnumerateFiles(directoryPath, "*", SearchOption.AllDirectories);Parallel.ForEach(files, file =>{Console.WriteLine(file); // 并行处理文件});}static void Main{ProcessFiles("path/to/large/directory");}}结合 yield 的方式，实现文件或目录的延迟加载。
using System;using System.Collections.Generic;using System.IO;class LazyLoadingExample{static IEnumerable GetFiles(string directoryPath){foreach (var file in Directory.EnumerateFiles(directoryPath, "*", SearchOption.AllDirectories)){yield return file;}}static void Main{foreach (var file in GetFiles("path/to/large/directory")){Console.WriteLine(File); // 按需加载文件}}}优点：仅在需要时加载数据。注意：延迟加载的实现受文件系统和内存管理的影响。将大规模文件或目录分块处理，避免一次性操作过多数据。
using System;using System.Collections.Generic;using System.IO;class ChunkProcessingExample{static IEnumerable> GetFileChunks(string directoryPath, int chunkSize){var files = new List;foreach (var file in Directory.EnumerateFiles(directoryPath, "*", SearchOption.AllDirectories)){files.Add(file);if (files.Count == chunkSize){yield return new List(files);files.Clear;}}if (files.Count > 0){yield return files;}}static void Main{foreach (var chunk in GetFileChunks("path/to/large/directory", 100)){foreach (var file in chunk){Console.WriteLine(file); // 处理每个分块}}}}使用 StreamReader 逐行读取文件，而不是一次性加载所有内容。示例：using System; using System.IO; class StreamReaderExample { static void ReadFile(string filePath) { using (var reader = new StreamReader(filePath)) { string line; while ((line = reader.ReadLine) != null) { Console.WriteLine(line); // 逐行读取文件 } } } static void Main { ReadFile("path/to/large/file.txt"); } }使用 using 块或显式调用 Dispose 方法释放文件句柄。示例：foreach (var file in Directory.EnumerateFiles("path/to/directory")) { using (var fileStream = File.OpenRead(file)) { // 处理文件 } }using System;using System.IO;class ExceptionHandlingExample{static void ProcessFiles(string directoryPath){try{foreach (var file in Directory.EnumerateFiles(directoryPath, "*", SearchOption.AllDirectories)){try{Console.WriteLine(File.ReadAllText(file)); // 处理文件内容}catch (UnauthorizedAccessException){Console.WriteLine($"Access denied: {file}");}catch (IOException ex){Console.WriteLine($"IO error: {file}, Message: {ex.Message}");}}}catch (DirectoryNotFoundException){Console.WriteLine("Directory not found.");}}static void Main{ProcessFiles("path/to/large/directory");}}以下代码实现一个大规模文件遍历工具，结合性能和内存优化策略。
using System;using System.IO;using System.Threading.Tasks;class FileTraversalTool{static void ProcessFiles(string directoryPath){try{Parallel.ForEach(Directory.EnumerateFiles(directoryPath, "*", SearchOption.AllDirectories), file =>{try{Console.WriteLine($"Processing: {file}");// 模拟文件处理逻辑File.ReadAllBytes(file);}catch (UnauthorizedAccessException){Console.WriteLine($"Access denied: {file}");}catch (IOException ex){Console.WriteLine($"IO error: {file}, Message: {ex.Message}");}});}catch (DirectoryNotFoundException){Console.WriteLine("Directory not found.");}}static void Main{string directoryPath = "path/to/large/directory";ProcessFiles(directoryPath);}}通过结合这些技术，能高效处理大规模文件和目录的遍历，同时避免性能和内存问题。
来源：面试八股文
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