ColumnIndex negative if culture is tr-TR

[mganss]

I encountered this when investigating mganss/ExcelMapper#87 (see there for demo file). Demo code:

System.Threading.Thread.CurrentThread.CurrentCulture = new CultureInfo("tr-TR");

var wb = WorkbookFactory.Create(@"example01.xlsx");
var sheet = wb.GetSheet("Analyses");
var row = sheet.GetRow(1);
var cells = row.Cells;
var cell = cells[0];

// row.FirstCellNum -> -1
// cell.ColumnIndex -> -1

If you change the culture to en-US the issue does not occur. This might be because of the Turkish-I Problem.

[tonyqus]

This is weird. Can you check if you can reproduce the issue with 2.4.1? Looks to be a issue caused by ThreadLocal variable. Is it possible that something returns null and then FirstCellNum returns -1?

[mganss]

It doesn't occur in 2.4.1 but does in 2.5.0.

Is it possible that something returns null and then FirstCellNum returns -1?

What do you mean exactly?

[tonyqus]

@mganss I followed your code. But I still cannot reproduce the issue with NPOI 2.5.2 release. Did I miss something?

[mganss]

The CurrentCulture property needs to be set before the call to WorkbookFactory.Create().

[tonyqus]

@mganss Thank you for the tip. I can reproduce the issue now.

[tonyqus]

I found the root cause but it's very weird behavior of regular expression match.

The issue occurs in CellReference.SeparateRefParts method while handling a CT_Cell with r="I1" (Cell Address).

private static Regex CELL_REF_PATTERN = new Regex("(\\$?[A-Z]+)?" + "(\\$?[0-9]+)?", RegexOptions.IgnoreCase);

When CultureInfo is tr-TR, CELL_REF_PATTERN.Match partially works. Although Match.Success==true, the group values are still empty string instead of 'I' and '1'.

Source Link

[tonyqus]

https://stackoverflow.com/questions/3550213/in-c-sharp-what-is-the-difference-between-toupper-and-toupperinvariant

The first answer explains the issue. To fix this issue, RegexOptions.CultureInvariant shoud pass to the Regex constructor.