/// <summary>
/// 指定單元格位置添加下拉項
/// </summary>
/// <param name="sheetIndex">指定頁</param>
/// <param name="startRow">起始行</param>
/// <param name="colIndex">指定列</param>
/// <param name="rowNumber">多少行</param>
/// <param name="vals">"A,B,C,ALL".Split(',')</param>
internal static void SetCellDropdownList(int sheetIndex, int startRow, int colIndex, int rowNumber, string[] vals)
{
ISheet sheet = workbook.GetSheetAt(sheetIndex);
// 定義數據驗證的幫助類
var validationHelper = new XSSFDataValidationHelper((XSSFSheet)sheet);
// 定義數據驗證的約束條件,這里是序列類型,即下拉列表
var validationConstraint = validationHelper.CreateExplicitListConstraint(vals);
// 設置數據驗證的范圍
var addressList = new CellRangeAddressList(startRow, startRow + rowNumber - 1, colIndex, colIndex);
// 創建數據驗證對象并設置其屬性
var validation = validationHelper.CreateValidation(validationConstraint, addressList);
//validation.ErrorStyle = DataValidation.ErrorStyle.Stop;
validation.ShowErrorBox = true;
validation.CreatePromptBox("請選擇一個選項", string.Join(",", vals));
// 將數據驗證添加到工作表
sheet.AddValidationData(validation);
}