Excel插件： EEPlus插件，NPOI插件；给单元格添加下拉列表

Excel.dll，EEPlus单元格添加下拉列表

FileInfo _info=new FileInfo(Path);

if(_info.Exists)
{
    _info.Delete();
    _info=new FileInfo(Path);

}

using(ExcelPackage pag = new ExcelPackage("文件名称"))
{
    ExcelWorksheet ws =pah.Workbook.Worksheets.Add("工作表名称");
    var unt = ws.DataValidations.AddListValidation("A1");
    unt.Formula.Values.Add("列表项");
    pag.Save();
}

NPOI插件

HSSFWorkbook workbook = new HSSFWorkbook();

ISheet sheet = workbook.CreateSheet("sheet1");

ExcelHelper.SetCellDropdownList(sheet, 1, 1, new List<string>() { "男", "女", "保密" }.ToArray());

public static void SetCellDropdownList(ISheet sheet, int firstcol, int lastcol, string[] vals)
{
     //设置生成下拉框的行和列
     var cellRegions = new CellRangeAddressList(1, 65535, firstcol, lastcol);
 
     //设置 下拉框内容
     DVConstraint constraint = DVConstraint.CreateExplicitListConstraint(vals);
 
     //绑定下拉框和作用区域，并设置错误提示信息
     HSSFDataValidation dataValidate = new HSSFDataValidation(cellRegions, constraint);
     dataValidate.CreateErrorBox("输入不合法", "请输入或选择下拉列表中的值。");
     dataValidate.ShowPromptBox = true;
 
     sheet.AddValidationData(dataValidate);
}

引用：C#设置Excel下拉选项(IT技术)