Strange error when creating Excel files with Spreadsheet_Excel_Writer

Question

Here's the code. Not much to it.

<?php
include("Spreadsheet/Excel/Writer.php");

$xls = new Spreadsheet_Excel_Writer();

$sheet = $xls->addWorksheet('At a Glance');

$colNames = array('Foo', 'Bar');
$sheet->writeRow(0, 0, $colNames, $colHeadingFormat);

for($i=1; $i<=10; $i++)
{
    $row = array( "foo $i", "bar $i");

    $sheet->writeRow($rowNumber++, 0, $row);
}

header ("Expires: " . gmdate("D,d M Y H:i:s") . " GMT");
header ("Last-Modified: " . gmdate("D,d M Y H:i:s") . " GMT");
header ("Cache-Control: no-cache, must-revalidate");
header ("Pragma: no-cache");
$xls->send("test.xls");
$xls->close();
?>

The issue is that I get the following error when I actually open the file with Excel:

File error:  data may have been lost.

Even stranger is the fact that, despite the error, the file seems fine. Any data I happen to be writing is there.

Any ideas on how to get rid of this error?

---

Edit

I've modified the code sample to better illustrate the problem. I don't think the first sample was a legit test.

Answer 1

Hmm I just installed it to test and didn't get an error - it said Foo like it should.

The file generated was 3,584 bytes; I opened it in Excel 2002

Answer 2

The code in the question has a bug which causes the error.

This line writes a bunch of column names to row 0

$sheet->writeRow(0, 0, $colNames, $colHeadingFormat);

Then we have the loop which is supposed to write out the value rows.

for($i=1; $i<=10; $i++)
{
    $row = array( "foo $i", "bar $i");

    $sheet->writeRow($rowNumber++, 0, $row);
}

The problem is that $rowNumber isn't declared anywhere so it overwrites row 0 on the first pass through the loop.

This overwriting seems to cause an issue with Excel Writer.

The strange thing is that, on the Excel file that gives the error, you still see the row with the column names even though it's technically been overwritten.

I found the solution here on Google Groups. Scroll down to the bottom. It's the last post by Micah that mentions the issue.

---

And here's the fix

<?php
include("Spreadsheet/Excel/Writer.php");

$xls = new Spreadsheet_Excel_Writer();

$rowNumber = 0;
$sheet = $xls->addWorksheet('At a Glance');

$colNames = array('Foo', 'Bar');
$sheet->writeRow($rowNumber, 0, $colNames, $colHeadingFormat);

for($i=1; $i<=10; $i++)
{
    $rowNumber++;
    $row = array( "foo $i", "bar $i");

    $sheet->writeRow($rowNumber, 0, $row);
}

header ("Expires: " . gmdate("D,d M Y H:i:s") . " GMT");
header ("Last-Modified: " . gmdate("D,d M Y H:i:s") . " GMT");
header ("Cache-Control: no-cache, must-revalidate");
header ("Pragma: no-cache");
$xls->send("test.xls");
$xls->close();
?>

Answer 3

As Mark Biek points out the main problem is that $rowNumber is uninitialised and as such overwrites row 0.

This means that the generated Excel file will contain 2 data entries for cells A1 and B1, (0, 0 and 0, 1).

This wasn't a problem prior to Office Service Pack 3. However, once SP3 is installed Excel will raise a "data may have been lost" warning if it encounters duplicate entries for a cell.

The general solution is to not write more than one data to a cell. :-)

Here is a more detailed explanation of the issue. It is in relation to the Perl Spreadsheet::WriteExcel module (from which the PHP module is derived) but the thrust is the same.

Answer 4

I got this error when writing to column 0 (A0) with PHPExcel. Excel is 1-indexed (A1), that's why it said "data may have been lost".

$this->m_excel->getActiveSheet()->SetCellValue($chr[$col].$row, $data));

$row was initialized to 0