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Excel doesn't close despite objects being released

So, I have a class that I wrote to handle opening excel files, however excel doesn't close even though I call the close function. This worked before I started using multiple workbooks so I presume that its something to do with that but I have no idea how to fix this. Any help appreciated!
This is the code:
public class ExcelReaderClass
{
public Excel.Application? excelApp = null; // create a null excell object that will later be used to store the reference to the open excel app
public Excel.Workbooks? excelBooks = null; // create a null object collection that will contain all workbooks
public Excel.Workbook? excelBook = null; // create a null object that will contain a workbook (excel file)
public Excel.Worksheet? curWorksheet = null; // create a null worksheet object that will contain the reference to the current worksheet that is open
public Excel.Range? curWorksheetRange = null; // create a range object that will contain the data from the currently open worksheet
// function that opens excel file and opens excel if it isnt already open
public void openExcelFile(string filePath) // filePath = filepath for the worksheet that is to be opened
{
if(excelApp == null) // if excel isnt open
{
excelApp = new Excel.Application(); // create a new instance of excel
excelApp.DisplayAlerts = false; // prevents "do you want to save" popups, which we want because we are only looking at files not changing them
excelBooks = excelApp.Workbooks; // create a new instance of workbook object collection
}
excelBook = excelBooks.Add(filePath); // add the workbook to the collection
}
// function that closes all instances of excel opened by this program
public void closeExcelFile(bool save, bool closeAll) // bool that controls whether only the worksheet is closed or the whole instance of excel
{
//excelBook.Save(); // save function not needed in this instance but might be useful later
GC.Collect();
GC.WaitForPendingFinalizers();
foreach (Excel.Workbook workbook in excelBooks)
{
workbook.Close(save, System.Reflection.Missing.Value, System.Reflection.Missing.Value); // close the workbook
NAR(workbook);
}
NAR(excelBooks); ; // release the workbook collection from Com
NAR(excelBook);
NAR(curWorksheet);
NAR(curWorksheetRange);
if (closeAll) // if close all is true, we want to close the excel instance too
{
excelApp.Quit(); // quit out of excel
NAR(excelApp); // release excel from Com
}
}
public List<object[,]> readExcelFile(string[] filePaths) //
{
List<object[,]> rangeList = new List<object[,]>(); // list of objects that will contain the data from the excel sheets
foreach (var filePath in filePaths) // for each file
{
openExcelFile(filePath); // open the file in excel
}
foreach (var workbook in excelBooks) // iterate through workbooks
{
var book = workbook as Excel.Workbook; // set book as a reference to the workbook
curWorksheet = book.Worksheets[1]; // set this variable to the first sheet in the workbook
curWorksheetRange = curWorksheet.UsedRange; // set this variable to the workbook range
object[,]? range = (object[,])curWorksheetRange.Value2;
rangeList.Add(range);
}
closeExcelFile(false,true);
return (rangeList);
}
//function to kill object and release it from COM
private void NAR(object o)
{
try
{
Marshal.FinalReleaseComObject(o);
}
catch { }
finally
{
o = null;
}
}
}
I've tried using GC.Collect() and GC.WaitForPendingFinalizers() but that doesn't seem to work either.

Update, this is what I did to fix the code. Feel free to use it. (Doesn't work in Debug mode though)
public class ExcelReaderClass
{
public Excel.Application? excelApp = null; // create a null excell object that will later be used to store the reference to the open excel app
public Excel.Workbooks? excelBooks = null; // create a null object collection that will contain all workbooks
public Excel.Workbook? excelBook = null; // create a null object that will contain a workbook (excel file)
public Excel.Worksheet? curWorksheet = null; // create a null worksheet object that will contain the reference to the current worksheet that is open
public Excel.Range? curWorksheetRange = null; // create a range object that will contain the data from the currently open worksheet
// function that opens excel file and opens excel if it isnt already open
public void openExcelFile(string filePath) // filePath = filepath for the worksheet that is to be opened
{
if(excelApp == null) // if excel isnt open
{
excelApp = new Excel.Application(); // create a new instance of excel
excelApp.DisplayAlerts = false; // prevents "do you want to save" popups, which we want because we are only looking at files not changing them
excelBooks = excelApp.Workbooks; // create a new instance of workbook object collection
}
excelBook = excelBooks.Add(filePath); // add the workbook to the collection
}
// function that closes all instances of excel opened by this program
public void closeExcelFile(bool save, bool closeAll) // bool that controls whether only the worksheet is closed or the whole instance of excel
{
foreach (Excel.Workbook workbook in excelBooks)
{
workbook.Close(save, System.Reflection.Missing.Value, System.Reflection.Missing.Value); // close the workbook
}
excelBooks = null; // clear the reference to the workbook collection
excelBook = null; // clear the reference to the active workbook
curWorksheet = null; // clear the reference to the current worksheet
curWorksheetRange = null; // clear the reference to the range of the current worksheet
if (closeAll) // if close all is true, we want to close the excel instance too
{
excelApp.Quit(); // quit out of excel
excelApp = null;
}
}
public List<object[,]> readExcelFile(string[] filePaths)
{
List<object[,]> rangeList = new List<object[,]>();
foreach (var filePath in filePaths)
{
openExcelFile(filePath);
}
Console.WriteLine();
foreach (var workbook in excelBooks) // done to select the first workbook because other methods have failed but this works
{
var book = workbook as Excel.Workbook; // set book as a reference to the workbook
curWorksheet = book.Worksheets[1]; // set this variable to the first sheet in the workbook
curWorksheetRange = curWorksheet.UsedRange; // set this variable to the workbook range
object[,]? range = (object[,])curWorksheetRange.Value2;
rangeList.Add(range);
}
closeExcelFile(false,true);
GC.Collect();
GC.WaitForPendingFinalizers();
return (rangeList);
}
}
Quick Rundown:
I deleted the NAR function and any places it was called, added GC.Collect() and GC.WaitForPendingFinalisers after all my excel code is executed, and made sure all variables are set to null before GC.* functions are called.

Microsoft.Office.Interop.Excel cells remain null after setting them

I have an application in which I'm trying to write to an Excel file. It doesn't seem to be working.
Here is my code:
using System;
using System.Drawing;
using Microsoft.Office.Interop.Excel;
namespace Image2Excel {
class Engine {
public static void go(string imageFilename, string excelFilename = null) {
//Image img = Image.FromFile(imageFilename);
Bitmap btm = (Bitmap)Bitmap.FromFile(imageFilename, false);
Image img = Image.FromFile(imageFilename, false);
if (btm != null) {
Color[][] colorArray = new Color[btm.Width][];
for (int x = 0; x < btm.Width; x++) {
colorArray[x] = new Color[btm.Height];
for (int y = 0; y < btm.Height; y++) {
colorArray[x][y] = btm.GetPixel(x, y);
}
}
var excel = new Microsoft.Office.Interop.Excel.Application();
var workbook = excel.Workbooks.Add(Type.Missing);
var worksheet = (Microsoft.Office.Interop.Excel.Worksheet)workbook.ActiveSheet;
worksheet.Name = "sheet1";
worksheet.Cells[1,1] = "top left";
worksheet.Cells[1,2] = "top right";
worksheet.Cells[2,1] = "bottom left";
worksheet.Cells[2,2] = "bottom right";
workbook.SaveAs("temp.xlsx");
workbook.Close();
excel.Quit();
Marshal.ReleaseComObject(worksheet);
Marshal.ReleaseComObject(workbook);
Marshal.ReleaseComObject(excel);
}
}
}
}
I'm trying to write some text to the first 4 cells in the spreadsheet. It's not working. When I open the file, I see nothing in the cells.
I do see that the sheet name is set to what I set it to so I know it's writing to the files.
One thing I noticed when I debug is that worksheet.Cells[1,1] is null after I set it. I'm wondering if I need to set the cell to an object before writing to it. But I'm not sure how. I don't seem to be able to do this:
worksheet.Cells[1,1] = new Microsoft.Office.Interop.Excel.Cell();
Hovering over Cells tells me it's a Range object, but I'm not sure how to set it to a range either. I tried this:
worksheet.Range["A1"].Value = "hello";
worksheet.Range["A1"].Value2 = "hello";
...but those don't work either. worksheet.Range remains null just like worksheet.Cells.
How can I make sure worksheet.Cells[1,1] or worksheet.Range["A1"] is set to an object that will take a string value? Thanks.
You can find my application on github: https://github.com/gibran-shah/Image2Excel
I'm using Microsoft.Office.Interop.Excel version 15.0.4795.1000.
I have Excel 2010 installed on my computer.

I haven't tried yours but could you try these methods? it worked for me.
1st method with Worksheets.Cells
// CREATE EXCEL OBJECTS.
Excel.Application xlApp;
Excel.Workbook xlWB;
Excel.Worksheet xlWS;
xlApp = new Excel.Application();
// Specify the path to the excel file
xlWB= xlApp.Workbooks.Open("path/to/xlFile.xls");
// Choose the sheet you want to open
xlWS = xlWB.Worksheets["Sheet1"];
// Write on the single cell
xlWS.Cells["1", "D"] = "Example";
// Save the change and quit
xlWB.Close(true);
xlApp.Quit();
2nd method with Worksheets.get_Range()
// CREATE EXCEL OBJECTS.
Excel.Application xlApp;
Excel.Workbook xlWB;
Excel.Worksheet xlWS;
xlApp = new Excel.Application();
// Specify the path to the excel file
xlWB= xlApp.Workbooks.Open("path/to/xlFile.xls");
// Choose the sheet you want to open
xlWS = xlWB.Worksheets["Sheet1"];
// Write on the range of cells
xlWS.get_Range["A3", "D5"] = "Example";
// Save the change and quit
xlWB.Close(true);
xlApp.Quit();

Excel process still runs in background

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();

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);

Long time no answer but what worked for me was to call the GC.Collect(); from the caller,
i.e. instead of
main()
{
...
doexcelstuff();
...
}
void doexcelstuff()
{
Excel.Application ExApp2 = new Excel.Application();
Excel.Workbook excelWb = ExApp2 .Workbooks.Open(excelFName);
Excel._Worksheet excelWorksheet = excelWb.Sheets[excelSName];
//...
excelWb.Close();
ExApp2.Quit();
Marshal.ReleaseComObject(excelWb);
Marshal.ReleaseComObject(excelWorksheet);
Marshal.ReleaseComObject(ExApp2);
excelWb = null;
excelWorksheet= null;
ExApp2= null;
GC.Collect();
}
Using above Excel does not die
but a very small change, to where the GC is called from
main()
{
...
doexcelstuff();
GC.Collect(); // <<-- moved the GC to here (the caller)
...
}
void doexcelstuff()
{
Excel.Application ExApp2 = new Excel.Application();
Excel.Workbook excelWb = ExApp2 .Workbooks.Open(excelFName);
Excel._Worksheet excelWorksheet = excelWb.Sheets[excelSName];
//...
excelWb.Close();
ExApp2.Quit();
Marshal.ReleaseComObject(excelWb);
Marshal.ReleaseComObject(excelWorksheet);
Marshal.ReleaseComObject(ExApp2);
excelWb = null;
excelWorksheet= null;
ExApp2= null;
// removed the GC from here
}
My guess is the garbage collector needs to also quietly clean up internally created temp values (including refs/pointers) from the heap - some of which I guess in this case are pointing to COM objects.
(Just takes a smidgen of understanding of how machines work underneath the source code.)

You are not closing your workbook. Close it and then release it before quitting the Excel application:
excelWorkbook.close();
Marshal.ReleaseComObject(excelWorkbook);
ExcelApp.Quit();

For me this worked!
//Initializing
Application excelApp = new Application();
Workbook excelWorkbook = excelApp.Workbooks.Open(pathExcelFile, 0, true, 5, "", "",
true, XlPlatform.xlWindows, "\t", false, false, 0,
true, 1, 0);
Worksheet excelWorksheet = (Worksheet)excelWorkbook.Sheets[1];
//closing
excelWorksheet = null;
excelWorkbook.Close();
excelWorkbook = null;
excelApp.Quit();
excelApp = null;

Interop is notoriously buggy... I use the following method after saving my workbook, and no longer have issues with Excel remaining open when I exit my applications:
while (Marshal.ReleaseComObject(wb) > 0);
while (Marshal.ReleaseComObject(xl) > 0);
wb = null;
xl = null;
GC.WaitForPendingFinalizers();
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();
wb is my workbook object, and xl is my Excel.Application object.

For me this worked :
//opening
var excelFile = new Application();
Workbook workBook1 = excelFile.Workbooks.Open(goldenCopy_path);
Workbook workBook2 = excelFile.Workbooks.Open(new_path);
Worksheet goldWorkSheet, newWorkSheet;
goldWorkSheet = workBook1.Worksheets[1];
newWorkSheet = workBook2.Worksheets[1];
//closing
//it will release the workbook from visual studio
goldWorkSheet = null;
newWorkSheet = null;
workBook1.Close();
workBook2.Close();
workBook1 = null;
workBook2 = null;
excelFile.Quit();
excelFile = null;

This code worked on me.
Excel.Application excelApp = null;
Excel.Workbooks excelWorkbooks = null;
Excel.Workbook excelWorkbook = null;
Excel._Worksheet xlWorkSheet = null;
Excel.Range range = null;
excelApp = new Excel.Application();
excelWorkbooks = excelApp.Workbooks;
excelWorkbook = excelWorkbooks.Open(excelName);
xlWorkSheet = (Excel.Worksheet)excelWorkbook.ActiveSheet;
range = xlWorkSheet.Range["C3"] ;
range.Value = "Update Data";
Marshal.ReleaseComObject(range);
xlWorkSheet.SaveAs(path);
Marshal.ReleaseComObject(xlWorkSheet);
excelWorkbook.Close();
Marshal.ReleaseComObject(excelWorkbook);
excelWorkbooks.Close();
Marshal.ReleaseComObject(excelWorkbooks);
excelApp.Quit();
Marshal.ReleaseComObject(excelApp);

Copy specific worksheets to new Excel file

I have an Excel file.
I need to open it, select specific sheets from it, and convert those sheets to a PDF format. I am able to convert the whole excel file, I just don't know how to convert only the specific sheets.
My idea is to copy specific sheets from an existing file to a new temporary file, and convert that whole new temporary file to PDF.
Maybe there's an easier way?
My code so far is =>
using Word = Microsoft.Office.Interop.Word;
using Excel = Microsoft.Office.Interop.Excel;
public static void ExportExcel(string infile, string outfile, int[] worksheets)
{
Excel.Application excelApp = null;
Excel.Application newExcelApp = null;
try
{
excelApp = new Excel.Application();
excelApp.Workbooks.Open(infile);
//((Microsoft.Office.Interop.Excel._Worksheet)excelApp.ActiveSheet).PageSetup.Orientation = Microsoft.Office.Interop.Excel.XlPageOrientation.xlLandscape;
excelApp.ActiveWorkbook.ExportAsFixedFormat(Excel.XlFixedFormatType.xlTypePDF, outfile);
}
finally
{
if (excelApp != null)
{
excelApp.DisplayAlerts = false;
excelApp.SaveWorkspace();
excelApp.Quit();
}
}
}
Maybe the ExportAsFixedFormat method can be set to consider only specific pages (sheets) while converting?
If not, how do I copy the sheets from one file to another?
Thanks!

You might be able to just print the sheets you want from the original file. I fired up the Macro Recorder, selected a couple of sheets, and Saved As to PDF. Here's the code:
Sheets(Array("Sheet1", "Sheet2")).Select
ActiveSheet.ExportAsFixedFormat Type:=xlTypePDF, Filename:= _
"C:\Users\doug\Documents\Book1.pdf", Quality:=xlQualityStandard, _
IncludeDocProperties:=True, IgnorePrintAreas:=False, OpenAfterPublish:=True
When I changed the selected sheets and ran again it worked as expected.
What's strange is that in the actual Save As dialog, you can go to Options and check "Selected Sheets." That's not available as a parameter to ExportAsFixedFormat, but it was automatically selected in the dialog, and maybe is the default also when called.

You could simply copy the file to the new destination, open the destination, remove the unwanted sheets and export. This is an example (tested) of my idea.
// infile is the excel file, outfile is the pdf to build, sheetToExport is the name of the sheet
public static void ExportExcel(string infile, string outfile, string sheetToExport)
{
Microsoft.Office.Interop.Excel.Application excelApp = new
Microsoft.Office.Interop.Excel.Application();
try
{
string tempFile = Path.ChangeExtension(outfile, "XLS");
File.Copy(infile, tempFile, true);
Microsoft.Office.Interop.Excel._Workbook excelWorkbook =
excelApp.Workbooks.Open(tempFile);
for(int x = excelApp.Sheets.Count; x > 0; x--)
{
_Worksheet sheet = (_Worksheet)excelApp.Sheets[x];
if(sheet != null && sheet.Name != sheetToExport)
sheet.Delete();
}
excelApp.ActiveWorkbook.ExportAsFixedFormat(XlFixedFormatType.xlTypePDF, outfile);
}
finally
{
if (excelApp != null)
{
excelApp.DisplayAlerts = false;
excelApp.SaveWorkspace();
excelApp.Quit();
}
}
}

How to get the selected sheet name in Excel using c#.net

Hi friends,
I am beginner for using Excel. I need to figure out how to find the selected sheet name from the workbook in Excel.
Thanks a lot.
Devaraj

This is a little old. In 2004, but I used it and it helped me. What I understand is you want to call a certain excel sheet to your c# app? Anyway, check this site out, it will help if thats what your doing.
C# - Retrieve Excel Workbook Sheet Names.

You can use this solution ....
Taken from here ....using excel oledb to get sheet names in sheet order
private Dictionary<int,string> GetExcelSheetNames(string fileName)
{
Excel.Application _excel = null;
Excel.Workbook _workBook = null;
Dictionary<int,string> excelSheets = new Dictionary<int,string>();
try
{
object missing = Type.Missing;
object readOnly = true;
Excel.XlFileFormat.xlWorkbookNormal
_excel = new Excel.ApplicationClass();
_excel.Visible = false;
_workBook = _excel.Workbooks.Open(fileName, 0, readOnly, 5, missing,
missing, true, Excel.XlPlatform.xlWindows, "\\t", false, false, 0, true, true, missing);
if (_workBook != null)
{
int index = 0;
foreach (Excel.Worksheet sheet in _workBook.Sheets)
{
// Can get sheet names in order they are in workbook
excelSheets.Add(++index, sheet.Name);
}
}
}
catch (Exception e)
{
return null;
}
finally
{
if (_excel != null)
{
if (_workBook != null)
{
_workBook.Close(false, Type.Missing, Type.Missing);
}
_excel.Application.Quit();
}
_excel = null;
_workBook = null;
}
return excelSheets;
}

Application xlsxApp;
string sheetname = (xlsxApp.ActiveSheet).Name;

Here is a more up to date answer:
Excel.Worksheet activeWorksheet = ((Excel.Worksheet)Application.ActiveSheet);
string activeWorksheetName = activeWorksheet.Name;
hth