Download Microsoft.office.interop.excel.dll Version 15.0.0.0 -

// Close the workbook and Excel application workbook.Close(); excelApp.Quit();

Microsoft.Office.Interop.Excel.dll is a .NET assembly that provides a set of .NET classes, interfaces, and enumerations that allow .NET developers to interact with Microsoft Office Excel. This assembly is part of the Microsoft Office Primary Interop Assemblies, which are a set of assemblies that enable .NET developers to automate and extend Microsoft Office applications. download microsoft.office.interop.excel.dll version 15.0.0.0

using Microsoft.Office.Interop.Excel;