Excel process still runs in background

Question

I'm reading some data from a sheet of an excel file using interop library. I get the data just fine by using Microsoft.Office.Interop.Excel and then reading all data in the sheet.

Application ExcelApp = new Excel.Application();
Workbook excelWorkbook = ExcelApp2.Workbooks.Open(excelFileNamePath);
_Worksheet excelWorksheet = excelWorkbook.Sheets[excelSheetName];
Range excelRange = excelWorksheet.UsedRange;
//...for loops for reading data
ExcelApp.Quit();

But after my application terminates, I tried to edit my excel file and had some problems while opening. Apparently the excel process keeps on running in the background even though I called ExcelApp.Quit(). Is there a way to properly close the excel file that the application uses? I'm new to c# so i'm probably missing something here.

Edit: Solved! Apparently there's a rule for com objects that discourages using 2 dots.

Excel.Application ExcelApp2 = new Excel.Application();
Excel.Workbooks excelWorkbooks = ExcelApp2.Workbooks;
Excel.Workbook excelWorkbook = excelWorkbooks.Open(excelFileName);
Excel._Worksheet excelWorksheet = excelWorkbook.Sheets[excelSheetName];
//...
excelWorkbook.Close();       
Marshal.ReleaseComObject(excelWorkbook);
Marshal.ReleaseComObject(excelWorksheet);
Marshal.ReleaseComObject(excelRange);
ExcelApp2.Quit();

Answer 1

There was another similar question - and answer (https://stackoverflow.com/a/17367570/3063884), in which the solution was to avoid using double-dot notation. Instead, define variables for each object used along the way, and individually use Marshal.ReleaseComObject on each one.

Copying straight from the linked solution:

var workbook = excel.Workbooks.Open(/*params*/)

---> instead use -->

var workbooks = excel.Workbooks;
var workbook = workbooks.Open(/*params*/)

Then, when done, release each COM object:

Marshal.ReleaseComObject(workbook);
Marshal.ReleaseComObject(workbooks);
Marshal.ReleaseComObject(excel);