// Initialize Excel engine and application
using ExcelEngine excelEngine = new ExcelEngine();
IApplication application = excelEngine.Excel;
application.DefaultVersion = ExcelVersion.Xlsx;
// Create a workbook and worksheet
IWorkbook workbook = application.Workbooks.Create(1);
IWorksheet worksheet = workbook.Worksheets[0];
// Data validation for lists
IDataValidation listValidation = worksheet.Range["C3"].DataValidation;
worksheet.Range["C1"].Text = "Data Validation List in C3";
worksheet.Range["C1"].AutofitColumns();
listValidation.ListOfValues = new string[] { "ListItem1", "ListItem2", "ListItem3" };
// Shows the error message
listValidation.ErrorBoxText = "Choose the value from the list";
listValidation.ErrorBoxTitle = "ERROR";
listValidation.PromptBoxText = "Data validation for list";
listValidation.IsPromptBoxVisible = true;
listValidation.ShowPromptBox = true;
// Save the Excel document
using FileStream outputStream = new FileStream("ListValidation.xlsx", FileMode.Create, FileAccess.Write);
workbook.SaveAs(outputStream);