以下是EPPlus的一些数字格式选项：

//integer (not really needed unless you need to round numbers, Excel will use default cell properties)
ws.Cells["A1:A25"].Style.Numberformat.Format = "0";

//integer without displaying the number 0 in the cell
ws.Cells["A1:A25"].Style.Numberformat.Format = "#";

//number with 1 decimal place
ws.Cells["A1:A25"].Style.Numberformat.Format = "0.0";

//number with 2 decimal places
ws.Cells["A1:A25"].Style.Numberformat.Format = "0.00";

//number with 2 decimal places and thousand separator
ws.Cells["A1:A25"].Style.Numberformat.Format = "#,##0.00";

//number with 2 decimal places and thousand separator and money symbol
ws.Cells["A1:A25"].Style.Numberformat.Format = "€#,##0.00";

//percentage (1 = 100%, 0.01 = 1%)
ws.Cells["A1:A25"].Style.Numberformat.Format = "0%";

//accounting number format
ws.Cells["A1:A25"].Style.Numberformat.Format = "_-$* #,##0.00_-;-$* #,##0.00_-;_-$* \"-\"??_-;_-@_-";

不要将小数点和千位分隔符更改为您自己的本地化。Excel会为您完成这些操作。
通过请求一些日期时间格式选项。

//default DateTime pattern
worksheet.Cells["A1:A25"].Style.Numberformat.Format = DateTimeFormatInfo.CurrentInfo.ShortDatePattern;

//custom DateTime pattern
worksheet.Cells["A1:A25"].Style.Numberformat.Format = "dd-MM-yyyy HH:mm";

除了接受的答案，因为value接受对象，你必须传递数字到值例如，如果你的输入是字符串：

var input = "5";    
ws.Cells["A1:A25"].Value = double.Parse(input);

另一个被接受的答案：你可以使用空值和格式都看起来不错，但它最终是一个字符串在Excel中，你不能求和，平均等。
因此，请确保使用nullable的实际Value。

如果你想格式化一个特定的列，如列“B”，以数字格式，你可以这样做-

using (var package = new ExcelPackage())
{
  var worksheet = package.Workbook.Worksheets.Add("SHEET1");
  worksheet.Cells["A1"].LoadFromDataTable(dataTable, PrintHeaders: true);
  for (var col = 1; col < dataTable.Columns.Count + 1; col++)
  {
    if (col == 2)//col number 2 is equivalent to column B
    {
      worksheet.Column(col).Style.Numberformat.Format = "#";//apply the number formatting you need
    }
    worksheet.Column(col).AutoFit();
  }
  return File(package.GetAsByteArray(), XlsxContentType, "report.xlsx");//downloads file
}

我解决了它如下，所以我只是加载模型，并根据我的模型改变，如果它是int或datetime

var li = typeof(Model)
              .GetProperties()
              .ToArray();

 using (var package = new ExcelPackage(stream))
            {
                var workSheet = package.Workbook.Worksheets.Add("Sheet1");

var i = 0;
                foreach (var c in li)
                {
                    i++;
                    if(c.PropertyType.Name == typeof(DateTime).Name || c.PropertyType.Name == typeof(DateTime?).Name)
                        workSheet.Column(i).Style.Numberformat.Format = DateTimeFormatInfo.CurrentInfo.ShortDatePattern; ;

                    if (c.PropertyType.Name == typeof(int).Name || c.PropertyType.Name == typeof(int?).Name)
                        workSheet.Column(i).Style.Numberformat.Format = "0";                    
                }

}