Vista - Excel does not die using automation

I have a vb.net app that opens an excel worksheet, reads data and then closes
the sheet. Im noticing that the Excel process is still running after I have
closed and disposed of my excel objects.

The following code (Test1) demonstrates the essence of what I am doing.
When I check the processes while ruinning the method, I notice that the Excel
process remains after exiting the sub (and until I exit the application)

Sub Test1
Dim objExcelApp As New Excel.Application

Dim objExcelWorkBook As Excel.Workbook =
objExcelApp.Workbooks.Open("C:\Test.xls")
Dim objExcelWorksheet As Excel.Worksheet = objExcelWorkBook.Sheets(1)

Dim objRange As Excel.Range
objRange = objExcelWorksheet.Range("A1")
MsgBox(objRange.Text)
''http://www.vbforums.com/archive/index.php/t-396405.html
objRange = Nothing
objExcelWorksheet = Nothing
objExcelWorkBook.Close()
objExcelWorkBook = Nothing
objExcelApp.Workbooks.Close()
objExcelApp.Quit()

System.Runtime.InteropServices.Marshal.ReleaseComObject(objExcelApp)

objExcelApp = Nothing

End Sub

When I strip the code dow to this (Test2) I notice that the process is
created on line
Dim objExcelApp As New Excel.Application
and killed on line
System.Runtime.InteropServices.Marshal.ReleaseComObject(objExcelApp)

Sub Test2
Dim objExcelApp As New Excel.Application

System.Runtime.InteropServices.Marshal.ReleaseComObject(objExcelApp)

objExcelApp = Nothing
End Sub


What is it that is keeping a reference to the Excel process and how do I
kill the process?

You must call ReleaseComObject(obj) on EACH COM object you've created.

That means on the Range, Worksheet, Workbook, Chart, PivotTable, etc.
objects one might instantiate within the Excel.Application.

"Terry Holland" <MSDNNospam248@xxxxxx> wrote in message
news:9B590AD1-E4A3-4EA8-84AA-8A0358F3673A@xxxxxx

Using the following as test code, the Excel process remains. Can you see a
reason for this?

Sub Test
Dim objExcelApp As New Excel.Application
Dim objExcelWorkBook As Excel.Workbook =
objExcelApp.Workbooks.Open("C:\Test.xls")
Dim objExcelWorksheet As Excel.Worksheet = objExcelWorkBook.Sheets(1)
Dim objRange As Excel.Range

objRange = objExcelWorksheet.Range("A1")
MsgBox(objRange.Text)

objExcelWorkBook.Close()
objExcelApp.Quit()

System.Runtime.InteropServices.Marshal.ReleaseComObject(objRange)

System.Runtime.InteropServices.Marshal.ReleaseComObject(objExcelWorksheet)

System.Runtime.InteropServices.Marshal.ReleaseComObject(objExcelWorkBook)
System.Runtime.InteropServices.Marshal.ReleaseComObject(objExcelApp)

objRange = Nothing
objExcelWorksheet = Nothing
objExcelWorkBook = Nothing
objExcelApp = Nothing
End Sub
"Scott M." wrote:

Are you checking to see if Excel is running when you are debugging your code
in Visual Studio?

If so, you shouldn't as this isn't going to give you an accurate
representation of processes. When I compile your code into an .exe and run
that .exe directly with Task Manager open, Excel comes up and then drops off
the list after my method call to do the Excel stuff finishes and my console
sits open waiting for input via a Console.Read.

-Scott

"Terry Holland" <MSDNNospam248@xxxxxx> wrote in message
news:29BA0CA5-F757-4233-B1ED-7DE4D13AC7B3@xxxxxx

I was doing this in debug mode. I have done as you suggested and run the
compiled exe (winforms). The excel process is still running after executing
the code. The process is only killed when the form is closed. I have no
other code on this form other than a button_click event to execute the code.

I then tried the same thing as console app as you have done and in my case
the excel process is running until the console window closes

Imports Microsoft.Office.Interop

Module Module1

Sub Main()
Dim objExcelApp As New Excel.Application
Dim objExcelWorkBook As Excel.Workbook =
objExcelApp.Workbooks.Open("C:\Test.xls")
Dim objExcelWorksheet As Excel.Worksheet = objExcelWorkBook.Sheets(1)
Dim objRange As Excel.Range

objRange = objExcelWorksheet.Range("A1")
Console.WriteLine(objRange.Text)
'Console.Read()


objExcelWorkBook.Close()
objExcelApp.Quit()

System.Runtime.InteropServices.Marshal.ReleaseComObject(objRange)

System.Runtime.InteropServices.Marshal.ReleaseComObject(objExcelWorksheet)

System.Runtime.InteropServices.Marshal.ReleaseComObject(objExcelWorkBook)
System.Runtime.InteropServices.Marshal.ReleaseComObject(objExcelApp)

objRange = Nothing
objExcelWorksheet = Nothing
objExcelWorkBook = Nothing
objExcelApp = Nothing

Console.WriteLine("Waiting")
Console.Read()
End Sub

End Module
"Scott M." wrote:

What version of .NET are you using? Excel closes in my console app when I
try.


"Terry Holland" <MSDNNospam248@xxxxxx> wrote in message
news:BE108C26-9B16-46B8-B343-B02E2EFDA1FE@xxxxxx

im using .net 2.0

"Scott M." wrote:

On Jul 6, 1:53*pm, Terry Holland <MSDNNospam...@xxxxxx> wrote:I don't know if it works for you, but if you have small workbooks you
can use
our GemBox.Spreadsheet Free (http://www.gemboxsoftware.com/
GBSpreadsheetFree.htm)
Excel component for XLS/CSV/XLSX reading/writing/reporting.
Automation has many issues: http://www.gemboxsoftware.com/GBSpre...htm#Automation

--Zeljko

It looks to me like you've created a race condition. You need to call
objExcelApp.Quit() after you've released all of the COM objects you've been
using (except for the excel application instance), not before.

Also, as you've done below make sure you release the objects inversely from
the order they were instantiated. The last object you created becomes the
first object you're releasing.

Other than that, your application looks fine to me.

"Terry Holland" wrote:

"Jeff Winn" <JeffWinn@xxxxxx> wrote in message
news:6AEC2118-C87D-4EDA-9560-AE84337F107A@xxxxxxI don't think this makes any difference whatsoever. The fact is that if you
explicitly create Excel objects and explictly release them (in the opposite
order you created them), you should have no trouble calling
ReleaseComObject() After quitting Excel.

As I said, I have the code working just fine:


Imports System.Runtime.InteropServices

Sub Test()
Dim objExcelApp As New Excel.Application
Dim objExcelWorkBook As Excel.Workbook =
objExcelApp.Workbooks.Open("C:\test.xls")
Dim objExcelWorksheet As Excel.Worksheet = objExcelWorkBook.Sheets(1)
Dim objRange As Excel.Range = objExcelWorksheet.Range("A1")
objExcelApp.Visible = True
objExcelWorkBook.Close()
objExcelApp.Quit()

Marshal.ReleaseComObject(objRange)
Marshal.ReleaseComObject(objExcelWorksheet)
Marshal.ReleaseComObject(objExcelWorkBook)
Marshal.ReleaseComObject(objExcelApp)

objRange = Nothing
objExcelWorksheet = Nothing
objExcelWorkBook = Nothing
objExcelApp = Nothing
End Sub