Problem Description:

嚴重的: >>org.zkoss.poi.ss.formula.eval.NotImplementedException: Error evaluating cell 'formula-datetime'!B6
>>org.zkoss.poi.ss.formula.eval.NotImplementedException: DATEVALUE, not in zk context
>> at org.zkoss.zssex.formula.ELEvalFunction.evaluate(ELEvalFunction.java:109)
>> at org.zkoss.poi.ss.formula.functions.NotImplementedFunction.evaluate(NotImplementedFunction.java:62)
>> at org.zkoss.poi.ss.formula.OperationEvaluatorFactory.evaluate(OperationEvaluatorFactory.java:132)
>> at org.zkoss.poi.ss.formula.WorkbookEvaluator.evaluateFormula(WorkbookEvaluator.java:539)
>> at org.zkoss.poi.ss.formula.WorkbookEvaluator.evaluateAny(WorkbookEvaluator.java:316)
>> at org.zkoss.poi.ss.formula.WorkbookEvaluator.evaluate(WorkbookEvaluator.java:255)
>> at org.zkoss.poi.xssf.usermodel.XSSFFormulaEvaluator.evaluateFormulaCellValue(XSSFFormulaEvaluator.java:266)
>> at org.zkoss.poi.xssf.usermodel.XSSFFormulaEvaluator.evaluate(XSSFFormulaEvaluator.java:119)
>> at org.zkoss.zss.model.sys.impl.BookHelper.evaluate(BookHelper.java:492)
>> at org.zkoss.zss.model.sys.impl.BookHelper.getFormatText(BookHelper.java:1034)
>> at org.zkoss.zss.ui.impl.XUtils.getFormatText(XUtils.java:355)
>> at org.zkoss.zss.ui.impl.CellFormatHelper.getHtmlStyle(CellFormatHelper.java:89)
>> at org.zkoss.zss.ui.Spreadsheet$ExtraCtrl.getCellAttr(Spreadsheet.java:3041)
>> at org.zkoss.zss.ui.Spreadsheet$ExtraCtrl.getRangeAttrs(Spreadsheet.java:2915)
>> at org.zkoss.zss.ui.Spreadsheet.updateSheetAttributes(Spreadsheet.java:839)
>> at org.zkoss.zss.ui.Spreadsheet.setSelectedSheetDirectly(Spreadsheet.java:778)
>> at org.zkoss.zss.ui.Spreadsheet.access$41(Spreadsheet.java:756)
>> at org.zkoss.zss.ui.Spreadsheet$ExtraCtrl.setSelectedSheetDirectly(Spreadsheet.java:3495)
>> at org.zkoss.zss.ui.au.in.SelectSheetCommand.process(SelectSheetCommand.java:87)
>> at org.zkoss.zss.ui.Spreadsheet.service(Spreadsheet.java:4760)

Reproducing Steps:

1. run the Spreadsheet
2. type the formula: =DATEVALUE("2008/1/1")

Expected:
evaluated value.

Actual:
An exception thrown like above.