The spreadsheet engine parsed typed input with the invariant culture while
displaying values with the current culture, breaking the edit round-trip on
non-en-US hosts and making comma-decimal entry (10,50) impossible.
Workbook gains a Culture property (defaults to CurrentCulture) which the
component stamps from its inherited Culture parameter. It drives:
- Cell input parsing (CellData type inference), including day-month date
handling for cultures where the group and date separators collide (de-DE)
- Edit text and display rendering (GetValue, GetValueAsString, GetDisplayText)
- Number format rendering - format codes stay canonical invariant tokens while
separators, month names, and AM/PM designators follow the culture
- Formula entry and display via the new FormulaLocalizer (Excel FormulaLocal
semantics: ';' argument separators and ',' decimals in comma-decimal
cultures, lenient comma acceptance where unambiguous, canonical invariant
storage)
- Dialog input (data validation, conditional format, filter) via shared
conversion helpers on SpreadsheetDialogBase
XLSX and CSV files read and write canonical invariant values regardless of
the workbook culture, including autofit column widths. Malformed formulas now
surface as error trees instead of an unhandled lexer exception. Number format
parsing is cached (hard-bounded) since CellView reparsed per render.
Includes localization demos for the Spreadsheet and Document Processing
sections and culture test suites.
Note: headless code on non-en-US hosts now parses string values with the
host culture; set Workbook.Culture explicitly (or to InvariantCulture) for
host-independent processing.
