如何在C#中将文件输出为带有签名的UTF8

问题描述 投票:0回答:1

我正在尝试将Excel文件作为附件输出到ASP.NET,很难用土耳其语对其进行编码。以下代码是我所做的;我将尝试尝试的行保留为注释:

  var collection = Data.Get<Students>()
    .Where(t => t.Year == activeYear)
    .OrderBy(t => t.Name);

  var total = collection.Count();

  DataTable dt = collection.ToDataTable();
  dt.Columns.Remove("Id");

  string htmlCode = "<table>";

  //add header row
  htmlCode += "<tr>";
  htmlCode += "<td>#</td>";

  for (int i = 0; i < dt.Columns.Count; i++)
  {
      htmlCode += "<td>" + dt.Columns[i].ColumnName + "</td>";
  }

  htmlCode += "</tr>";

  //add rows
  for (int i = 0; i < dt.Rows.Count; i++)
  {
    htmlCode += "<tr>";
    htmlCode += "<td>" + (dt.Rows.Count-i+1).ToString() + "</td>";

    for (int j = 0; j < dt.Columns.Count; j++)
    {
        htmlCode += "<td>" + dt.Rows[i][j].ToString() + "</td>";
    }

    htmlCode += "</tr>";
  }

  htmlCode += "</table>";   


  ////////////////////////////////////
  // Encoding part begins here
  ////////////////////////////////////

  var output = htmlCode;

  Encoding encoding =  new UTF8Encoding(true); //Encoding.UTF8; //new UTF8Encoding(true);
  var utf8bytes = encoding.GetBytes(output);
  utf8bytes = Encoding.UTF8.GetPreamble().Concat(utf8bytes).ToArray();
  byte[] bytes = new UTF8Encoding(true).GetBytes(output);
  //MemoryStream stream = new MemoryStream(utf8bytes);
  MemoryStream stream = new MemoryStream(bytes);

  StreamReader reader = new StreamReader(stream);

  Response.Clear();
  Response.Buffer = true;
  Response.ClearContent();

  string attachment = "attachment; filename=" + Utils.Security.RemoveDiacritics(currentLesson + "-" + activeYear) + ".xls";
  Response.AddHeader("content-disposition", attachment);
  //Response.ContentType = "application/octet-stream";
  Response.ContentType = "application/vnd.ms-excel";

  Response.ContentEncoding = new UTF8Encoding(true); //Encoding.GetEncoding("windows-1254"); // Encoding.UTF8;
  Response.Output.Write(reader.ReadToEnd());
  Response.Flush();
  Response.End();

如果我使用新的UTF8Encoding(true)或false,则输出始终是没有签名的UTF8。如果我在Notepad2中打开文件并使用签名将其编码为UTF8,则名称将正确显示。

这是下载的Excel文件,并且在Excel中名称不正确:

img

这是记事本2中经过修改的Excel文件,并且名称在Excel中显示正确:

enter image description here

要更正名称,我用Notepad2打开下载的xls文件,并将编码从UTF8更改为具有签名的UTF8。现在,如何在服务器端执行此操作?

更新:文件之间的区别如下所示,显示在HEX编辑器屏幕快照中,在xls纯文本文件的开头仅添加了3个字节:

enter image description here

c# utf-8 character-encoding
1个回答
0
投票

如果要使用utf-8和bom发送字节列表,则应将3个字节写在头部。

您可以将三个字节0xEF,0xBB,0xBF写入您的字节列表头以使字节列表成为带Bom编码的utf-8

请参阅Byte order mark - Wikipedia

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