Excel interop COM doesn't close

Question

I have some code that opens a spreadsheet, reads some values, and then closes the sheet. I need to do this for multiple files. The problem I\'m having is that the Excel applic

Answer 1

I wanted to share some of my experiences with respect to this same problem.

I re-structured my Excel Interop code to ensure I never have more than one property period, following the "rules" stated within this webpage: http://jake.ginnivan.net/vsto-com-interop/

Ex:

• I removed strings like the following...

ExcelApplication.ExcelWorkbook.Workbookworksheet.WorksheetRange.Range.Count

(exaggerated a bit).

-I replaced such strings with items like the following...

var CurrentRange = currentMDL.CurrentMDL_xlRange;
var CurrentRangeColumns = CurrentRange.Columns;
var CurrentRangeWorksheet = currentMDL.CurrentMDL_Worksheet;
var CurrentRangeWorksheetCells = CurrentRangeWorksheet.Cells;

From here, I am able to tap into what I want much more cleanly.

Ex:

for(int i = 1; i <= CurrentRangeColumns.Count; i++)
{
//Doing stuff
}

I made sure to close my Excel document within the same method in which it was opened, after all of my operations took place. I plan on re-visiting this to see if i am able to close the Excel documents remotely.

Lastly, I made sure to follow up with some releases of all my COM objects used within my Excel handling methods.

Ex:

Marshal.FinalReleaseComObject(CurrentRange);
Marshal.FinalReleaseComObject(CurrentRangeCells);
Marshal.FinalReleaseComObject(CurrentRangeRows);

The order of operations matter here. I made sure to close my workbook, then Excel application, then finally released my COM objects. I spoke with an engineer I work with, regarding the usage of ComObject release. He says that I shouldn't need to use those calls, because garbage collection should eventually clean up my mess. With my studies here, I could not get garbage collection to close out my instances of Excel and opted to release them myself.

-Chris