``` // <summary>? ??????? /// 創建固定大小的臨時文件? ??????? /// </summary>? ??????? /// <param name="fileName">文件名</param>? ??????? /// <param name="fileSize">文件大小</param>? ??????? /// <param name="overwrite">允許覆寫：可以覆蓋掉已經存在的文件</param>? ??????? public static void CreateFixedSizeFile(string fileName, long fileSize) ??????? { ??????????? //驗證參數? ??????????? if (string.IsNullOrEmpty(fileName) || new[] { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar }.Contains( ??????????????????? fileName[fileName.Length - 1])) ??????????????? throw new ArgumentException("fileName"); ??????????? if (fileSize < 0) throw new ArgumentException("fileSize"); ??????????? //創建目錄? ??????????? string dir = Path.GetDirectoryName(fileName); ??????????? if (!string.IsNullOrEmpty(dir) && !Directory.Exists(dir)) ??????????????? Directory.CreateDirectory(dir); ??????????? //創建文件? ??????????? FileStream fs = null; ??????????? try ??????????? { ??????????????? fs = new FileStream(fileName, FileMode.Create); ??????????????? fs.SetLength(fileSize); //設置文件大小? ??????????? } ??????????? catch ??????????? { ??????????????? if (fs != null) ??????????????? { ??????????????????? fs.Close(); ??????????????????? File.Delete(fileName); //注意，若由fs.SetLength方法產生了異常，同樣會執行刪除命令，請慎用overwrite:true參數，或者修改刪除文件代碼。? ??????????????? } ??????????????? throw; ??????????? } ??????????? finally ??????????? { ??????????????? if (fs != null) fs.Close(); ??????????? } ??????? } ??????? /// <summary> ??????? /// 讀取大文件用,讀取文件前面指定長度字節數 ??????? /// </summary> ??????? /// <param name="filePath">文件路徑</param> ??????? /// <param name="readByteLength">讀取長度,單位字節</param> ??????? /// <returns></returns> ??????? public byte[] ReadBigFile(string filePath,int readByteLength) ??????? {? ??????????? FileStream stream = new FileStream(filePath,FileMode.Open); ??????????? byte[] buffer = new byte[readByteLength]; ??????????? stream.Read(buffer, 0, readByteLength); ??????????? stream.Close(); ??????????? stream.Dispose(); ??????????? return buffer; ??????????? //string str = Encoding.Default.GetString(buffer) //如果需要轉換成編碼字符串的話 ??????? } ??????? /// <summary> ??????? /// 普通文件讀取方法 ??????? /// </summary> ??????? /// <param name="path"></param> ??????? /// <returns></returns> ??????? public string ReaderFile(string path) ??????? { ??????????? string fileData = string.Empty; ??????????? ///讀取文件的內容????? ??????????? StreamReader reader = new StreamReader(path, Encoding.Default); ??????????? fileData = reader.ReadToEnd(); ??????????? reader.Close(); ??????????? reader.Dispose(); ??????????? return fileData; ??????? } ``` 原文鏈接：https://blog.csdn.net/u013628121/article/details/52577702