I have a bit of code that opens an xls workbook;
Excel.Workbooks workBooks;
workBooks = excelApp.Workbooks;
workbook = workBooks.Open(sourceFilePath + sourceFileName + ".xls");
I then get the work sheet;
worksheets = workbook.Worksheets;
worksheet = worksheets.get_Item("Standard");
I then save the file as a csv;
worksheet.SaveAs(sourceFilePath + sourceFileName + ".csv", Excel.XlFileFormat.xlCSVWindows, Type.Missing, Type.Missing, false, false, Excel.XlSaveAsAccessMode.xlNoChange, Type.Missing, Type.Missing, Type.Missing);
Then I try to close the workbook;
Marshal.FinalReleaseComObject(worksheet);
Marshal.FinalReleaseComObject(worksheets);
workbook.Close();
Marshal.FinalReleaseComObject(workbook);
However, every time i get to the line workbook.Close(), the system stops.
If I do not do the SaveAs then the workbook closes just fine.
How do I close a workbook?
edit
Looking at Task Manager shows me that Excel.exe is still running. Closing it will produce an error in my code.
edit 2
I have already seen the referenced SO post and it did not solve the issue.
Here is the solution
first:
using EXCEL = Microsoft.Office.Interop.Excel;
and then, path is where your excel locates.
EXCEL.Application excel = new EXCEL.Application();
try
{
EXCEL.Workbook book = excel.Application.Workbooks.Open(path);
EXCEL.Worksheet sheet = book.Worksheets[1];
// yout operation
}
catch (Exception ex) { MessageBox.Show("readExcel:" + ex.Message); }
finally
{
KillExcel(excel);
System.Threading.Thread.Sleep(100);
}
[DllImport("User32.dll")]
public static extern int GetWindowThreadProcessId(IntPtr hWnd, out int ProcessId);
private static void KillExcel(EXCEL.Application theApp)
{
int id = 0;
IntPtr intptr = new IntPtr(theApp.Hwnd);
System.Diagnostics.Process p = null;
try
{
GetWindowThreadProcessId(intptr, out id);
p = System.Diagnostics.Process.GetProcessById(id);
if (p != null)
{
p.Kill();
p.Dispose();
}
}
catch (Exception ex)
{
System.Windows.Forms.MessageBox.Show("KillExcel:" + ex.Message);
}
}
Why not combine the 2. This will take care of any problems with closing before saving is complete.
There is an option in the Close method to save the file.
workbook.Close(true, fileName, Missing.Value);
Also if the file is saving correctly, and your problem is purely because the excel.exe process is still running, it could be because you didn't close and release EVERYTHING needed. I have had this before and developed a more complete close down routine. My code for shutting down an excel file is:
book.Close(true, fileName, Missing.Value); //close and save individual book
allBooks.Close(); //close all books
excel.Quit();
Marshal.ReleaseComObject(allCells); //any used range objects
Marshal.ReleaseComObject(sheet);
Marshal.ReleaseComObject(sheets);
Marshal.ReleaseComObject(book);
Marshal.ReleaseComObject(allBooks);
Marshal.ReleaseComObject(excel);
This works 100% of the time for me.
Have you considered the fact that the system might still be in the process of saving the file when you attempt to close it? I'm just saying, to be sure add a delay(Thread.Sleep(1000) in C# for example) before the close to see if this is the problem.
This question keeps popping up see:
How to properly clean up Excel interop objects in C#
You need to call System.Runtime.InteropServices.Marshal.ReleaseComObject() on every excel object you use, even invisible ones, e.g.:
var worksheet = excelApp.Worksheets.Open()
There are two objects here:
1. The obvious 'Worksheet' opened with Open()
2. The "invisible" collection 'Worksheets'.
Both of them need to be released (so you better keep a reference for Worksheets):
var wkCol = excelApp.Worksheets;
var worksheet = wkCol.Open();
EXCEL.Application excel = new EXCEL.Application();
try
{
EXCEL.Workbook book = excel.Application.Workbooks.Open(path);
EXCEL.Worksheet sheet = book.Worksheets[1];
// yout operation
}
catch (Exception ex) { MessageBox.Show("readExcel:" + ex.Message); }
finally
{
KillExcel(excel);
System.Threading.Thread.Sleep(100);
}
[DllImport("User32.dll")]
public static extern int GetWindowThreadProcessId(IntPtr hWnd, out int ProcessId);
private static void KillExcel(EXCEL.Application theApp)
{
int id = 0;
IntPtr intptr = new IntPtr(theApp.Hwnd);
System.Diagnostics.Process p = null;
try
{
GetWindowThreadProcessId(intptr, out id);
p = System.Diagnostics.Process.GetProcessById(id);
if (p != null)
{
p.Kill();
p.Dispose();
}
}
catch (Exception ex)
{
System.Windows.Forms.MessageBox.Show("KillExcel:" + ex.Message);
}
}
Thank you!!!!
This work for me. EXCEL.EXE will be kill after close you program.
Excel.Application objExcel;
Excel._Workbook objBook;
Excel.Workbooks objBooks;
Excel._Worksheet objSheet;
Excel.Sheets objSheets;
objExcel = new Excel.Application();
objBooks = objExcel.Workbooks;
objBook = objExcel.Workbooks.Open(Application.StartupPath+#"/"+"template.xls");
objSheets = objBook.Worksheets;
objSheet = (Excel._Worksheet)objBook.ActiveSheet;
//....you code modify excel book
objBook.Close(true, objBook, Missing.Value);
objExcel.Quit();
Marshal.ReleaseComObject(objSheet);
Marshal.ReleaseComObject(objSheets);
Marshal.ReleaseComObject(objBook);
Marshal.ReleaseComObject(objBooks);
Marshal.ReleaseComObject(objExcel);
Related
I am trying to close excel process in my winform application. I have gone through lots of posts on SO and other sites and this is what I am doing right now:
private void lsvSelectedQ_SelectedIndexChanged(object sender, EventArgs e)
{
FillSelectedItems();
}
private void FillSelectedItems()
{
string filepath = string.Empty;
string reportname = lblreportname.Text;
filepath = Application.StartupPath + "\\StandardReports\\" + reportname + ".xls";
Microsoft.Office.Interop.Excel.Application xlApp;
Microsoft.Office.Interop.Excel.Workbook xlWorkBook;
Microsoft.Office.Interop.Excel.Worksheet xlWorkSheet;
object misValue = System.Reflection.Missing.Value;
xlApp = new Microsoft.Office.Interop.Excel.Application();
xlWorkBook = xlApp.Workbooks.Open(filepath, 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);
List<string> WorksheetList = new List<string>();
xlWorkSheet = (Microsoft.Office.Interop.Excel.Worksheet)xlWorkBook.Worksheets.get_Item("Config");
Microsoft.Office.Interop.Excel.Range objRange = null;
objRange = (Microsoft.Office.Interop.Excel.Range)xlWorkSheet.Cells[6, 2];
if (objRange.Value != null)
{
int intSheet = Convert.ToInt32(objRange.Value);
for (int i = 0; i < intSheet; i++)
{
objRange = (Microsoft.Office.Interop.Excel.Range)xlWorkSheet.Cells[6, 3+i ];
if (objRange.Value != null)
{
lsvSelectedQ.Items.Add(Convert.ToString(objRange.Value));
}
}
}
ReleaseMyExcelsObjects(xlApp, xlWorkBook, xlWorkSheet);
}
In the above code I am using ReleaseMyExcelsObjects method to get rid of running excel process in the taskbar.
private void ReleaseMyExcelsObjects(Microsoft.Office.Interop.Excel.Application xlApp, Microsoft.Office.Interop.Excel.Workbook xlWorkBook, Microsoft.Office.Interop.Excel.Worksheet xlWorkSheet)
{
xlApp.DisplayAlerts = false;
xlWorkBook.Save();
xlWorkBook.Close();
xlApp.DisplayAlerts = false;
xlApp.Quit();
System.Runtime.InteropServices.Marshal.ReleaseComObject(xlWorkSheet);
System.Runtime.InteropServices.Marshal.ReleaseComObject(xlWorkBook);
System.Runtime.InteropServices.Marshal.ReleaseComObject(xlApp);
xlWorkSheet = null;
xlWorkBook = null;
xlApp = null;
GC.Collect();
}
As you can see I open an excel on a SelectedIndexChanged and I am also trying to close the process through ReleaseMyExcelsObjects() method and it works except for the first excel process that is generated. I mean when the event is fired the excel process is started and ReleaseMyExcelsObjects() does not close it however the second time SelectedIndexChanged is fired, another excel process is started. This time ReleaseMyExcelsObjects() closes this second excel process. But the first excel process which was started when theSelectedIndexChanged event was fired for the first time never gets closed.
EDIT:
I have posted an answer myself which is getting the job done. But I am going to keep this question open if in case someone comes up with better solution.
I have found a work around for this:
[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern int GetWindowThreadProcessId(int hWnd, out int lpdwProcessId);
public static Process GetExcelProcess(Microsoft.Office.Interop.Excel.Application excelApp)
{
int id;
GetWindowThreadProcessId(excelApp.Hwnd, out id);
return Process.GetProcessById(id);
}
Use it as classobj.GetExcelProcess(xlApp).Kill();
Taken from : https://stackoverflow.com/a/15556843/2064292
from my understanding, the ReleaseComObject closes the Excel Application when your C# application exits. Thus, a new Excel processes will show up in your taskbar every time you call FillSelectedItems() which won't close until you exit your C# application.
EDIT: On a side note, I recommend using try, catch, finally when handling the excel interop library, mainly due to the fact that if the application runs into an exception, the program will not exit normally, and as stated before it will result on the excel process remaining in the taskbar (and when you manually open said file on excel it will tell you the last recovered version blablabla)
string filepath = string.Empty;
string reportname = lblreportname.Text;
filepath = Application.StartupPath + "\\StandardReports\\" + reportname + ".xls";
Microsoft.Office.Interop.Excel.Application xlApp;
Microsoft.Office.Interop.Excel.Workbook xlWorkBook;
Microsoft.Office.Interop.Excel.Worksheet xlWorkSheet;
object misValue = System.Reflection.Missing.Value;
xlApp = new Microsoft.Office.Interop.Excel.Application();
xlWorkBook = xlApp.Workbooks.Open(filepath, 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);
List<string> WorksheetList = new List<string>();
try
{
//Your code
}
catch (Exception ex) { MessageBox.Show(string.Format("Error: {0}", ex.Message)); }
finally
{
xlWorkBook.Close(false, filepath, null);
Marshal.ReleaseComObject(xlWorkBook);
}
Honestly, if you are annoyed by this, I would recommend using EPPlus or ExcelDataReader(this one only for reading the excel spreadsheets) as alternative libraries. Otherwise, No matter how many releaseComObjects or garbagecollectors you add, I believe you wont get rid of this issue.
EDIT 2: Of course, another way to go around this is to search for an Excel process ID and kill it. The reason I did not recommend this, is because in the event that the user who's running this application already has another excel process running on his computer, you could end up killing that instance.
I have a solution for closing the Excel process. Instead of going thru the pains of releasing your objects, you can kill that specific excel process (if you have multiple of them open).
The code is:
using System;
using System.Runtime.InteropServices;
using Microsoft.Office.Interop.Excel;
namespace YourNameSpace
{
public class MicrosoftApplications
{
[DllImport("user32.dll")]
static extern int GetWindowThreadProcessId(int hWnd, out int lpdwProcessId);
public class Excel
{
public Excel()
{
Application = new Microsoft.Office.Interop.Excel.Application();
RegisterExitEvent();
}
public Microsoft.Office.Interop.Excel.Application Application;
private void RegisterExitEvent()
{
Application.WindowDeactivate -= XlApp_WindowDeactivate;
Application.WindowDeactivate += XlApp_WindowDeactivate;
}
private void XlApp_WindowDeactivate(Workbook Wb, Window Wn)
{
Kill();
}
public void Kill()
{
int pid = 0;
GetWindowThreadProcessId(Application.Hwnd, out pid);
if (pid > 0)
{
System.Diagnostics.Process p = System.Diagnostics.Process.GetProcessById(pid);
p.Kill();
}
Application = null;
GC.Collect();
GC.WaitForPendingFinalizers();
}
}
}
}
And you can call it by: YourNameSpace.MicrosoftApplications.Excel xlApp = new YourNameSpace.MicrosoftApplications.Excel();
Do whatever you need to do by calling xlApp.Application.whatever instead of xlApp.whatever and if the user exits the excel window(s) it will kill the process(es) that were used in the code. If you want to just generate a report behind the scenes but not display the form, then simply call xlApp.Kill(); to end that specific process.
I want to check if excel is open. If it is, I want to save the active workbook and close excel. Essentially, my goal is to kill every excel process, but before doing so I want to save the excel workbook. This is my code...
Process[] localByName = Process.GetProcessesByName("excel");
for (int i = 0; i < localByName.Length; i++)
{
Microsoft.Office.Interop.Excel.Application xlApp = new Microsoft.Office.Interop.Excel.Application();
Workbook wb = xlApp.ActiveWorkbook;
wb.Save(); // I get an error here. "Object reference not set to an instance of an object".
GC.Collect();
GC.WaitForPendingFinalizers();
wb.Close();
Marshal.FinalReleaseComObject(wb);
xlApp.Quit();
Marshal.FinalReleaseComObject(xlApp);
}
I read that xlApp.ActiveWorkbook gets the workbook in read only mode. Could this be my problem? If so please propose a successful way to go about this. Thank you!
> Microsoft.Office.Interop.Excel.Application xlApp = new Microsoft.Office.Interop.Excel.Application(); this creates a new instance of the Excel.Application COM Object and does not return an active instance. To do so, try
Excel.Application xlApp = null;
while(xlApp == null)
{
try
{
xlApp = (Excel.Application)System.Runtime.InteropServices.Marshal.GetActiveObject("Excel.Application");
}
catch (System.Runtime.InteropServices.COMException ex)
{
// no more instances/error, exit out of loop
break;
}
// do whatever with the instance
Workbook wb = xlApp.ActiveWorkbook;
wb.Save();
GC.Collect();
GC.WaitForPendingFinalizers();
wb.Close();
Marshal.FinalReleaseComObject(wb);
xlApp.Quit();
Marshal.FinalReleaseComObject(xlApp);
// set null to continue loop
xlApp = null;
}
Source: Get instance of Excel application with C# by Handle
I have made a small class that takes an excel workbook, graps the contained charts in the workbook and export each of them to PNG files.
It almost works fine, but I have a problem regarding the generated PNG files, the class doesn't close the files properly, until the user closes the application.
Here is my class:
public List<string> ExportCharts(string fileName)
{
var exportedGraphsList = new List<string>();
Excel.Workbooks xlWorkBooks = null;
Excel.Workbook xlWorkBook = null;
Excel.Application xlApp = null;
Excel.Sheets xlSheets = null;
object misValue = System.Reflection.Missing.Value;
try
{
xlApp = new Excel.ApplicationClass();
xlWorkBooks = xlApp.Workbooks;
xlWorkBook = xlWorkBooks.Open(fileName);
xlSheets = xlWorkBook.Charts;
foreach (Excel.Chart xlChart in xlSheets)
{
var exportfileName = ConfigurationManager.AppSettings["imageSavePath"] + #"\" + xlChart.Name + ".png";
xlChart.Export(exportfileName, "PNG", misValue);
exportedGraphsList.Add(exportfileName);
}
return exportedGraphsList;
}
catch (Exception ex)
{
MessageBox.Show(ex.Message + "\n\n" + ex.StackTrace, "Der gik noget galt");
exportedGraphsList.Clear();
return exportedGraphsList;
}
finally
{
GC.Collect();
GC.WaitForPendingFinalizers();
if(xlSheets != null)
Marshal.FinalReleaseComObject(xlSheets);
if (xlWorkBook != null)
{
xlWorkBook.Close(false, Type.Missing, Type.Missing);
Marshal.FinalReleaseComObject(xlWorkBook);
}
if (xlWorkBooks != null)
Marshal.FinalReleaseComObject(xlWorkBooks);
if (xlApp != null)
{
xlApp.Quit();
Marshal.FinalReleaseComObject(xlApp);
}
}
}
public void Dispose()
{
GC.Collect();
GC.WaitForPendingFinalizers();
}
When this method is invoked, it starts and closes the Excel proces very nicely, but the PNG files remains open. I could of coruse put a timestamp on the exported filesnames, but I fear it will confuse the user.
Thanks in advance for any hints or ideas. :-)
Solved - it was due to the fact that I loaded the image files afterwards to the GUI.
So Excel.InterOp works fine.
This question already has answers here:
How do I properly clean up Excel interop objects?
(43 answers)
Closed 9 years ago.
I've got this C# program that never closes the Excel process. Basically it finds the number of instances a string appears in a range in Excel. I've tried all kinds of things, but it's not working. There is a Form that is calling this method, but that shouldn't change why the process isn't closing. I've looks at suggestions by Hans Passant, but none are working.
EDIT: I tried the things mentioned and it still won't close. Here's my updated code.
EDIT: Tried the whole Process.Kill() and it works, but it seems like a bit of a hack for something that should just work.
public class CompareHelper
{
// Define Variables
Excel.Application excelApp = null;
Excel.Workbooks wkbks = null;
Excel.Workbook wkbk = null;
Excel.Worksheet wksht = null;
Dictionary<String, int> map = new Dictionary<String, int>();
// Compare columns
public void GetCounts(string startrow, string endrow, string columnsin, System.Windows.Forms.TextBox results, string excelFile)
{
results.Text = "";
try
{
// Create an instance of Microsoft Excel and make it invisible
excelApp = new Excel.Application();
excelApp.Visible = false;
// open a Workbook and get the active Worksheet
wkbks = excelApp.Workbooks;
wkbk = wkbks.Open(excelFile, Type.Missing, true);
wksht = wkbk.ActiveSheet;
...
}
catch
{
throw;
}
finally
{
GC.Collect();
GC.WaitForPendingFinalizers();
if (wksht != null)
{
//wksht.Delete();
Marshal.FinalReleaseComObject(wksht);
wksht = null;
}
if (wkbks != null)
{
//wkbks.Close();
Marshal.FinalReleaseComObject(wkbks);
wkbks = null;
}
if (wkbk != null)
{
excelApp.DisplayAlerts = false;
wkbk.Close(false, Type.Missing, Type.Missing);
Marshal.FinalReleaseComObject(wkbk);
wkbk = null;
}
if (excelApp != null)
{
excelApp.Quit();
Marshal.FinalReleaseComObject(excelApp);
excelApp = null;
}
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();
GC.WaitForPendingFinalizers();
/*
Process[] processes = Process.GetProcessesByName("EXCEL");
foreach (Process p in processes)
{
p.Kill();
}
*/
}
}
}
Here is an interesting knowledge base on the subject of office apps staying open after a .NET app disconnects from them.
Office application does not quit after automation from Visual Studio .NET client
The code examples are all in the link (vb.net sorry). Basically it shows you how to correctly setup and tear down the office app so that it closes when you're finished with it.
System.Runtime.InteropServices.Marshal.FinalReleaseComObject is where the magic happens.
EDIT: You need to call the FinalReleaseComObject for each excel object that you've created.
if (excelWorkSheet1 != null)
{
Marshal.FinalReleaseComObject(excelWorkSheet1);
excelWorkSheet1 = null;
}
if (excelWorkbook != null)
{
Marshal.FinalReleaseComObject(excelWorkbook);
excelWorkbook = null;
}
if (excelApp != null)
{
Marshal.FinalReleaseComObject(excelApp);
excelApp = null;
}
I finally got it to close. You need to add a variable for the Workbooks collection, and then use the FinalReleaseComObject as stated in the other answers. I guess every possible Excel COM object that you use must be disposed this way.
try
{
// Create an instance of Microsoft Excel and make it invisible
excelApp = new Excel.Application();
excelApp.DisplayAlerts = false;
excelApp.Visible = false;
// open a Workbook and get the active Worksheet
excelWorkbooks = excelApp.Workbooks;
excelWorkbook = excelWorkbooks.Open(excelFile, Type.Missing, true);
excelWorkSheet1 = excelWorkbook.ActiveSheet;
}
catch
{
throw;
}
finally
{
NAR( excelWorkSheet1 );
excelWorkbook.Close(false, System.Reflection.Missing.Value, System.Reflection.Missing.Value);
NAR(excelWorkbook);
NAR(excelWorkbooks);
excelApp.Quit();
NAR(excelApp);
}
}
private void NAR(object o)
{
try
{
System.Runtime.InteropServices.Marshal.FinalReleaseComObject( o );
}
catch { }
finally
{
o = null;
}
}
DotNet only release the COM object after all the handles have been released. What I do is comment everything out, and then add back a portion. See if it release Excel. If it did not follow the following rules. When it release, add more code until it does not release again.
1) When you create your Excel variables, set all the values to null (this avoid not initiated errors)
2) Do not reuse variables without releasing it first Marshal.FinalReleaseComObject
3) Do not double dot (a.b = z). dotNet create a temporary variable, which will not get released.
c = a.b;
c = z;
Marshal.FinalReleaseComObject(c);
4) Release ALL excel variables. The quicker the better.
5) Set it back to NULL.
Set culture to "en-US". There is a bug that crash Excel with some cultures. This ensure it won't.
Here is an idea of how your code should be structured:
thisThread.CurrentCulture = new System.Globalization.CultureInfo("en-US");
InteropExcel.Application excelApp = null;
InteropExcel.Workbooks wkbks = null;
InteropExcel.Workbook wkbk = null;
try
{
excelApp = new InteropExcel.Application();
wkbks = excelApp.Workbooks;
wkbk = wkbks.Open(fileName);
...
}
catch (Exception ex)
{
}
if (wkbk != null)
{
excelApp.DisplayAlerts = false;
wkbk.Close(false);
Marshal.FinalReleaseComObject(wkbk);
wkbk = null;
}
if (wkbks != null)
{
wkbks.Close();
Marshal.FinalReleaseComObject(wkbks);
wkbks = null;
}
if (excelApp != null)
{
// Close Excel.
excelApp.Quit();
Marshal.FinalReleaseComObject(excelApp);
excelApp = null;
}
// Change culture back from en-us to the original culture.
thisThread.CurrentCulture = originalCulture;
}
I'm running into an issue with some code I'm debugging. Excel interop is used to extract some values from a workbook; however, Excel remains open after the program has exited. I've tried the traditional solution, but it still keeps a reference to Excel open on all machines where the code is run
private void TestExcel()
{
Excel.Application excel = new Excel.Application();
Excel.Workbooks books = excel.Workbooks;
Excel.Workbook book = books.Open("C:\\test.xlsm");
book.Close();
books.Close();
excel.Quit();
Marshal.ReleaseComObject(book);
Marshal.ReleaseComObject(books);
Marshal.ReleaseComObject(excel);
}
Even this simple piece of code keeps the process running with multiple files (xlsm, xlsx, xls). Right now we have a workaround in place to kill the Excel processes we've opened, but I'd much rather get this working for my own sanity.
I should add that I have it narrowed down to the Workbook variable. If I remove the call to books.Open() and all references to book then it closes successfully.
This has worked successfully for me:
xlApp.Quit();
//release all memory - stop EXCEL.exe from hanging around.
if (xlWorkBook != null) { Marshal.ReleaseComObject(xlWorkBook); } //release each workbook like this
if (xlWorkSheet != null) { Marshal.ReleaseComObject(xlWorkSheet); } //release each worksheet like this
if (xlApp != null) { Marshal.ReleaseComObject(xlApp); } //release the Excel application
xlWorkBook = null; //set each memory reference to null.
xlWorkSheet = null;
xlApp = null;
GC.Collect();
This code works for me.
//Declare separate object variables
Excel.Application xlApp = new Excel.Application();
Excel.Workbooks xlWorkbooks = xlApp.Workbooks;
Excel.Workbook xlWorkbook = xlWorkbooks.Add(Missing.Value);
Excel.Worksheet xlWorksheet = (Excel.Worksheet)xlWorkbook.Worksheets.get_Item(1);
//Create worksheet
xlWorkbook.Close(false, Missing.Value, Missing.Value);
xlWorkbooks.Close();
xlApp.Quit();
Marshal.FinalReleaseComObject(xlWorksheet);
Marshal.FinalReleaseComObject(xlWorkbook);
Marshal.FinalReleaseComObject(xlWorkbooks);
Marshal.FinalReleaseComObject(xlApp);
xlWorksheet = null;
xlWorkbook = null;
xlWorkbooks = null;
xlApp = null;
GC.Collect();
This article from Microsoft has some good information regarding this issue.
I am a total COM amateur, used it for a minor thing in one project quite a long time ago, but here's a snippet I used there. I probably found it somewhere online, don't remember. In any case, I paste it its full glory ;)
public static class ComBlackBox
{
public static void ReleaseObject(object obj)
{
try
{
System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
obj = null;
}
catch (ArgumentException ex)
{
obj = null;
MessageBox.Show("Unable to release the Object " + ex.Message);
}
finally
{
GC.Collect();
}
}
}
I'm unable to try it out now, but it probably worked (I honestly don't remember any details). Maybe it will help you out. Feel free to point out any obvious problems with this code, I really am far from being COM-literate ;)
This is how I got around this problem:
// Store the Excel processes before opening.
Process[] processesBefore = Process.GetProcessesByName("excel");
// Open the file in Excel.
Application excelApplication = new Application();
Workbook excelWorkbook = excelApplication.Workbooks.Open(Filename);
// Get Excel processes after opening the file.
Process[] processesAfter = Process.GetProcessesByName("excel");
// Now find the process id that was created, and store it.
int processID = 0;
foreach (Process process in processesAfter)
{
if (!processesBefore.Select(p => p.Id).Contains(process.Id))
{
processID = process.Id;
}
}
// Do the Excel stuff
// Now close the file with the COM object.
excelWorkbook.Close();
excelApplication.Workbooks.Close();
excelApplication.Quit();
// And now kill the process.
if (processID != 0)
{
Process process = Process.GetProcessById(processID);
process.Kill();
}