C# 文件操作的工具类

  根据查阅的资料对代码进行修改并完善备注后的结果。希望能对新手有所帮助。
  1 using System; using System.IO;
 namespace 文件操作类
 {
     public class FileHelper
     {
         /// <summary>
         /// 判断文件是否存在
         /// </summary>
         /// <param name="filePath">文件全路径</param>
         /// <returns></returns>
         public static bool Exists(string filePath)
         {
             if (filePath == null || filePath.Trim() == "")
             {
                 return false;
             }

             if (File.Exists(filePath))
             {
                 return true;
             }

             return false;
         }

         /// <summary>
         /// 创建文件夹
         /// </summary>
         /// <param name="dirPath">文件夹路径</param>
         /// <returns></returns>
         public static bool CreateDir(string dirPath)
         {
             if (!Directory.Exists(dirPath))
             {
                 Directory.CreateDirectory(dirPath);
             }
             return true;
         }

         /// <summary>
         /// 创建文件
         /// </summary>
         /// <param name="filePath">文件路径</param>
         /// <returns></returns>
         public static bool CreateFile(string filePath)
         {
             if (!File.Exists(filePath))
             {
                 FileStream fs = File.Create(filePath);
                 fs.Close();
                 fs.Dispose();
             }
             return true;

         }

         /// <summary>
         /// 读文件内容
         /// </summary>
         /// <param name="filePath">文件路径</param>
         /// <param name="encoding">编码格式</param>
         /// <returns></returns>
         public static string Read(string filePath,Encoding encoding)
         {
             if (!Exists(filePath))
             {
                 return null;
             }
             //将文件信息读入流中
             using (FileStream fs = new FileStream(filePath,FileMode.Open))
             {
                 return new StreamReader(fs, encoding).ReadToEnd();
             }
         }

         /// <summary>
         /// 读取文件的一行内容
         /// </summary>
         /// <param name="filePath">文件路径</param>
         /// <param name="encoding">编码格式</param>
         /// <returns></returns>
         public static string ReadLine(string filePath, Encoding encoding)
         {
             if (!Exists(filePath))
             {
                 return null;
             }
             using (FileStream fs = new FileStream(filePath, FileMode.Open))
             {
                 return new StreamReader(fs, encoding).ReadLine();
             }
         }

         /// <summary>
         /// 写文件
         /// </summary>
         /// <param name="filePath">文件路径</param>
         /// <param name="content">文件内容</param>
         /// <returns></returns>
         public static bool Write(string filePath, string content)
         {
             if (!Exists(filePath) || content == null)
             {
                 return false;
             }

             //将文件信息读入流中
             using (FileStream fs = new FileStream(filePath, FileMode.OpenOrCreate))
             {
                 lock (fs)//锁住流
                 {
                     if (!fs.CanWrite)
                     {
                         throw new System.Security.SecurityException("文件filePath=" + filePath + "是只读文件不能写入!");
                     }

                     byte[] buffer = Encoding.Default.GetBytes(content);
                     fs.Write(buffer, , buffer.Length);
                     return true;
                 }
             }
         }

         /// <summary>
         /// 写入一行
         /// </summary>
         /// <param name="filePath">文件路径</param>
         /// <param name="content">内容</param>
         /// <returns></returns>
         public static bool WriteLine(string filePath, string content)
         {
             using (FileStream fs = new FileStream(filePath, FileMode.OpenOrCreate | FileMode.Append))
             {
                 lock (fs)
                 {
                     if (!fs.CanWrite)
                     {
                         throw new System.Security.SecurityException("文件filePath=" + filePath + "是只读文件不能写入!");
                     }

                     StreamWriter sw = new StreamWriter(fs);
                     sw.WriteLine(content);
                     sw.Dispose();
                     sw.Close();
                     return true;
                 }
             }
         }

         public static bool CopyDir(DirectoryInfo fromDir, string toDir)
         {
             return CopyDir(fromDir, toDir, fromDir.FullName);
         }

         /// <summary>
         /// 复制目录
         /// </summary>
         /// <param name="fromDir">被复制的目录路径</param>
         /// <param name="toDir">复制到的目录路径</param>
         /// <returns></returns>
         public static bool CopyDir(string fromDir, string toDir)
         {
             if (fromDir == null || toDir == null)
             {
                 throw new NullReferenceException("参数为空");
             }

             if (fromDir == toDir)
             {
                 throw new Exception("两个目录都是" + fromDir);
             }

             if (!Directory.Exists(fromDir))
             {
                 throw new IOException("目录fromDir=" + fromDir + "不存在");
             }

             DirectoryInfo dir = new DirectoryInfo(fromDir);
             return CopyDir(dir, toDir, dir.FullName);
         }

         /// <summary>
         /// 复制目录
         /// </summary>
         /// <param name="fromDir">被复制的目录路径</param>
         /// <param name="toDir">复制到的目录路径</param>
         /// <param name="rootDir">被复制的根目录路径</param>
         /// <returns></returns>
         private static bool CopyDir(DirectoryInfo fromDir, string toDir, string rootDir)
         {
             string filePath = string.Empty;
             foreach (FileInfo f in fromDir.GetFiles())
             {
                 filePath = toDir + f.FullName.Substring(rootDir.Length);
                 string newDir = filePath.Substring(, filePath.LastIndexOf("\\"));
                 CreateDir(newDir);
                 File.Copy(f.FullName, filePath, true);
             }

             foreach (DirectoryInfo dir in fromDir.GetDirectories())
             {
                 CopyDir(dir, toDir, rootDir);
             }

             return true;
         }

         /// <summary>
         /// 删除文件
         /// </summary>
         /// <param name="filePath">文件的完整路径</param>
         /// <returns></returns>
         public static bool DeleteFile(string filePath)
         {
             if (Exists(filePath))
             {
                 File.Delete(filePath);
                 return true;
             }
             return false;
         }

         public static void DeleteDir(DirectoryInfo dir)
         {
             if (dir == null)
             {
                 throw new NullReferenceException("目录不存在");
             }

             foreach (DirectoryInfo d in dir.GetDirectories())
             {
                 DeleteDir(d);
             }

             foreach (FileInfo f in dir.GetFiles())
             {
                 DeleteFile(f.FullName);
             }

             dir.Delete();

         }

         /// <summary>
         /// 删除目录
         /// </summary>
         /// <param name="dir">指定目录路径</param>
         /// <param name="onlyDir">是否只删除目录</param>
         /// <returns></returns>
         public static bool DeleteDir(string dir, bool onlyDir)
         {
             if (dir == null || dir.Trim() == "")
             {
                 throw new NullReferenceException("目录dir=" + dir + "不存在");
             }

             if (!Directory.Exists(dir))
             {
                 return false;
             }

             DirectoryInfo dirInfo = new DirectoryInfo(dir);
             if (dirInfo.GetFiles().Length ==  && dirInfo.GetDirectories().Length == )
             {
                 Directory.Delete(dir);
                 return true;
             }

             if (!onlyDir)
             {
                 return false;
             }
             else
             {
                 DeleteDir(dirInfo);
                 return true;
             }

         }

         /// <summary>
         /// 在指定的目录中查找文件
         /// </summary>
         /// <param name="dir">目录路径</param>
         /// <param name="fileName">文件名</param>
         /// <returns></returns>
         public static bool FindFile(string dir, string fileName)
         {
             if (dir == null || dir.Trim() == "" || fileName == null || fileName.Trim() == "" || !Directory.Exists(dir))
             {
                 return false;
             }

             DirectoryInfo dirInfo = new DirectoryInfo(dir);
             return FindFile(dirInfo, fileName);

         }

         public static bool FindFile(DirectoryInfo dir, string fileName)
         {
             foreach (DirectoryInfo d in dir.GetDirectories())
             {
                 if (File.Exists(d.FullName + "\\" + fileName))
                 {
                     return true;
                 }
                 FindFile(d, fileName);
             }

             return false;
         }

     }
 }

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