//This example uses the ValidationError event.
var nCondition = new GC.Spread.Sheets.ConditionalFormatting.Condition(GC.Spread.Sheets.ConditionalFormatting.ConditionType.cellValueCondition);
nCondition.compareType(GC.Spread.Sheets.ConditionalFormatting.ComparisonOperators.equalsTo);
nCondition.expected(0);
//When the option is false, the validation fails and the red alert is displayed.
//When the option is true, the blank cell is treated as zero and the validation is successful.
nCondition.treatNullValueAsZero(false);
var validator = new GC.Spread.Sheets.DataValidation.DefaultDataValidator(nCondition)
validator.ignoreBlank(false);
activeSheet.getCell(0, 0, GC.Spread.Sheets.SheetArea.viewport).validator(validator);
spread.options.highlightInvalidData = true;
activeSheet.setValue(0, 0, null);
//Type different values in cell (0,0). This event fires if the user types an invalid value.
activeSheet.bind("ValidationError", vError);
function vError(sender, args) {
     alert("error");
}