默认Excel文档为

代码如下   需要下载  "EPPlus.Core"

var file = Directory.GetCurrentDirectory() + "\\Demo.xlsx";            using (var source = System.IO.File.OpenRead(file))            using (var excel = new OfficeOpenXml.ExcelPackage(source))            {                excel.Workbook.Worksheets[1].Cells[3, 1].Value = 123;                excel.Workbook.Worksheets[1].Cells[3, 2].Value = 张三;                excel.Workbook.Worksheets[1].Cells[3, 3].Value = 29;                var newfile = Directory.GetCurrentDirectory() + "\\new.xlsx";                var newfileinfo = new FileInfo(newfile);                excel.SaveAs(newfileinfo);            }

完成会生成如下Excel