Hi.
I tried to do the same for the example in this article, but there was no drop-down list. It also did not accept the values on the list.
CellIndex dataValidationRuleCellIndex = new CellIndex(0, 0); ListDataValidationRuleContext context = new ListDataValidationRuleContext(worksheet, dataValidationRuleCellIndex); context.InputMessageTitle = "Restricted input"; context.InputMessageContent = "The input is restricted to the week days."; context.ErrorStyle = ErrorStyle.Stop; context.ErrorAlertTitle = "Wrong value"; context.ErrorAlertContent = "The entered value is not valid. Allowed values are the week days!"; context.InCellDropdown = true; context.Argument1 = "Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday"; ListDataValidationRule rule = new ListDataValidationRule(context); worksheet.Cells[dataValidationRuleCellIndex].SetDataValidationRule(rule);

