EPPlus导入导出不占用进程

导入：

 using (ExcelPackage package = new ExcelPackage(new FileStream(openFile.FileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)))
 {
     ExcelWorksheet sheet = package.Workbook.Worksheets[];
     object title = sheet.Cells[, ].Value ?? "";
     // do
     int row = ;
 }

导出

 using (var package = new ExcelPackage(new FileInfo(sfd.FileName)))
 {
     var sheet = package.Workbook.Worksheets.Add("Abc");
     int rowIndex = ;
     sheet.Cells[rowIndex, ].Value = "日期";
     sheet.Cells.AutoFitColumns();
     sheet.Cells[, , rowIndex, ].Style.Border.Left.Style = ExcelBorderStyle.Thin;
     sheet.Cells[, , rowIndex, ].Style.Border.Top.Style = ExcelBorderStyle.Thin;
     sheet.Cells[, , rowIndex, ].Style.Border.Right.Style = ExcelBorderStyle.Thin;
     sheet.Cells[, , rowIndex, ].Style.Border.Bottom.Style = ExcelBorderStyle.Thin;
     package.Save();
     package.Dispose();
 }