[C#] 檔案寫入UTF8 或 UTF8 BOM

簡介

一開始使用靜態函式Encoding.UTF8寫入txt檔時，產生檔案為UTF8 with BOM，為了輸出UTF8 without BOM做一下筆記。

UTF8 / UTF8 BOM

• 產生UTF8 BOM

  Encoding utf8 = new UTF8Encoding(true);
  

• 產生UTF8

  Encoding utf8 = new UTF8Encoding(false);
  

• 簡單實作

  class Program
  {
      static void Main(string[] args)
      {
          string utf8file = "utf8file.txt";
  
          if (File.Exists(utf8file))
          {
              File.Delete(utf8file);
          }
  
          using (FileStream fileStream = new FileStream(utf8file, FileMode.Append, FileAccess.Write))
          {
              // Create a UTF-8 encoding.
              using (StreamWriter sw = new StreamWriter(fileStream, new UTF8Encoding(false)))
              {
                  sw.WriteLine("Hello world! (UTF8)");
              }
          }
  
  
          string utf8bomfile = "utf8bomfile.txt";
          if (File.Exists(utf8bomfile))
          {
              File.Delete(utf8bomfile);
          }
  
          using (FileStream fileStream = new FileStream(utf8bomfile, FileMode.Append, FileAccess.Write))
          {
              // Encoding.UTF8 同 new UTF8Encoding(true)
              // Create a UTF-8 encoding that supports a BOM.
              using (StreamWriter sw = new StreamWriter(fileStream, new UTF8Encoding(true)))
              {
                  sw.WriteLine("Hello world! (UTF8 Bom)");
              }
          }
  
      }
  }
  

  產生結果:
  

  

• 比較
  

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參考資料

• UTF8Encoding Class

如有錯誤或建議，歡迎留言指教，謝謝!!

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