Downloading .xlsx formating issue

Question

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I am trying to download an .xlsx report using the following code.
Error :: Excel cannot open the file ecause the file format and extension is not valid.
My report contents consist of two tabular structure in HTML format.
My data limit will always exceed 1 lakh plus records.
Kindly suggest any alternative for the same.

C#

  HttpContext.Current.Response.ContentType = "application/application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
           HttpContext.Current.Response.Write(@"<!DOCTYPE HTML PUBLIC ""-//W3C//DTD HTML 4.0 Transitional//EN"">");
           HttpContext.Current.Response.AppendHeader("content-disposition", "attachment;filename=Reports.xlsx");
           HttpContext.Current.Response.Charset = "utf-8";
           HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("windows-1250");
           HttpContext.Current.Response.Write("<font style='font-size:10.0pt; font-family:Calibri;'>");

HttpContext.Current.Response.Write("<BR><BR><BR>");
           HttpContext.Current.Response.Write("<Table border='1' bgColor='#ffffff' borderColor='#000000' cellSpacing='0' cellPadding='0' style='font-size:10.0pt; font-family:Calibri;'> <TR>");

additional information copied from comment below
No im not using Open XML.
I am using HTML table format to create the response in .xlsx format

C#

HttpContext.Current.Response.Write("<Table border='1' bgColor='#ffffff' borderColor='#000000' cellSpacing='0' cellPadding='0' style='font-size:10.0pt; font-family:Calibri;'> <TR>");
int columnscount = dtHeader.Columns.Count;

for (int j = 0; j < columnscount; j++)
{
   HttpContext.Current.Response.Write("<Td>");
   HttpContext.Current.Response.Write("");
   HttpContext.Current.Response.Write(dtHeader.Columns[j].ColumnName.ToString());
   HttpContext.Current.Response.Write("");
   HttpContext.Current.Response.Write("</Td>");
}

HttpContext.Current.Response.Write("</TR>");
foreach (DataRow row in dtHeader.Rows)
{
   HttpContext.Current.Response.Write("<TR>");
   for (int i = 0; i < dtHeader.Columns.Count; i++)
   {
      HttpContext.Current.Response.Write("<Td>");
      HttpContext.Current.Response.Write(row[i].ToString());
      HttpContext.Current.Response.Write("</Td>");
   }

   HttpContext.Current.Response.Write("</TR>");
}
HttpContext.Current.Response.Write("</Table>");

Posted 18-Nov-14 0:07am

Member-515487

Updated 18-Nov-14 4:41am

Nelek

v2

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Comments

Nathan Minier 18-Nov-14 7:06am

Where are you actually building the Excel filestream? Are you using OpenXML?

Member-515487 18-Nov-14 7:33am

No im not using Open XML.
I am using HTML table format to create the response in .xlsx format

HttpContext.Current.Response.Write("<Table border='1' bgColor='#ffffff' borderColor='#000000' cellSpacing='0' cellPadding='0' style='font-size:10.0pt; font-family:Calibri;'> <TR>");
int columnscount = dtHeader.Columns.Count;

for (int j = 0; j < columnscount; j++)
{
HttpContext.Current.Response.Write("<Td>");
HttpContext.Current.Response.Write("");
HttpContext.Current.Response.Write(dtHeader.Columns[j].ColumnName.ToString());
HttpContext.Current.Response.Write("");
HttpContext.Current.Response.Write("</Td>");
}
HttpContext.Current.Response.Write("</TR>");
foreach (DataRow row in dtHeader.Rows)
{
HttpContext.Current.Response.Write("<TR>");
for (int i = 0; i < dtHeader.Columns.Count; i++)
{
HttpContext.Current.Response.Write("<Td>");
HttpContext.Current.Response.Write(row[i].ToString());
HttpContext.Current.Response.Write("</Td>");
}

HttpContext.Current.Response.Write("</TR>");
}
HttpContext.Current.Response.Write("</Table>");

Nathan Minier 18-Nov-14 7:38am

That's likely your problem, then. The xlsx file format has certain requirements and it is a binary format, the plain-text that you're trying to push down simply is not in the correct format to be interpreted as that file type.

1 solution

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Treat my content as plain text, not as HTML

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johannesnestler · Answer 1 · 2014-11-18T04:26:00

Solution 1

I just see you creating a html doc, not an xlsx - So why you wonder about the error message - which is very expressive - wrong format and extension not matching - So the solution should be: either create a valid xlsx or a html, don't you agree?

Posted 18-Nov-14 4:26am

johannesnestler