PHPExcel Protect a single column - cell

Question

I have issues with cell protection.
I would like to protect just one column, B for example.
So I tried:
$sheet->getProtection()->setSheet(true);
$highestRow = $sheet->getHighestRow();
$sheet->getStyle('A1:J2000)->getProtection()->setLocked( PHPExcel_Style_Protection::PROTECTION_UNPROTECTED );
for($i=1;$i<=$highestRow;$i++)
{
$sheet->getStyleByColumnAndRow(1,$i)->getProtection()->setLocked(PHPExcel_Style_Protection::PROTECTION_PROTECTED);
}
But it's really slow, and not good because if I need to open my sheet again
$highestRow = $sheet->getHighestRow(); will return "J".
Another solution would be to get the last non-empty column, do you know how to do that? Because getHighestRow(Column) return the columns unprotected or empty.

Answer 1

The loop is slow because you're applying the style to each individual cell, rather than to the range of cells demonstrated in your
$sheet->getStyle('A1:J2000)->getProtection()->setLocked( PHPExcel_Style_Protection::PROTECTION_UNPROTECTED );
line
: one call to set the style for a range of 1000 cells is more that 1000 times faster than applying it to each of 1000 cells individually.
$sheet->getHighestDataRow();
will return the highest row in the worksheet that contains actual data values
$sheet->getHighestDataColumn();
is the column equivalent

Answer 2

First you can protect complete sheet. After that you can uprotect others. This code will protect the first column and first
$objPHPExcel->getActiveSheet()->getProtection()->setSheet(true);
$objPHPExcel->getActiveSheet()->getStyle('B2:Z400')->getProtection()->setLocked(PHPExcel_Style_Protection::PROTECTION_UNPROTECTED);