Unloading COM Objects C# [duplicate]

Question

Possible Duplicate:
How to properly clean up Excel interop objects in C#

I am using EXCEL INTEROP for reading excel files in my .NET application. However I see that after am done with it, I still see the EXCEL.EXE in Windows Task Manager.

The code is as follows:

ApplicationClass excel = new ApplicationClass();
Workbooks workBooks = excel.Workbooks;
Workbook workBook = workBooks.Open(fileName,0,true,5,"","",true,XLPlatform.xlWindows,"\t",false,false,0,true,1,0);


foreach (Name name in workBook.Names)
                {
                    try
                    {
                        // =#REF!#REF! indicates that the named range refers to nothing. Ignore these..
                        if (name.Value != "=#REF!#REF!")
                        {
                            if (!retNamedRanges.ContainsKey(name.Name))
                            {
                                string keyName = name.Name;
                                object value = name.RefersToRange.get_Value(missing);
                                retNamedRanges.Add(keyName, value);
                            }
                        }
                    }
                    catch (Exception ex)
                    {

                    }
                }



if(workBook!=null)
{
    workBook.Close(false,missing,missing);
}
if(workBook!=null)
{
    workBooks.Close();
}
System.Runtime.InteropServices.Marshal.ReleaseComObject(workBook);
System.Runtime.InteropServices.Marshal.ReleaseComObject(workBooks);
workBook = null;
workBooks = null;
excel.Application.Quit();
excel.Quit();
excel = null;

I have tried to do all possible things to clean up, but still it does not go. There are multiple EXCEL files that I need to read. Typically after my application executes I see multiple instances of EXCEL.EXE.

Is there anything else am missing with the clean up?

Many thanks in advance

Hey alex. I went through it yesterday and tried the above code. It did not help!!! — Nishant
– Nishant, Commented Sep 27, 2011 at 15:55

Jeremy McGee · Accepted Answer · 2011-09-27 12:30:27Z

0

"Some process specific to my application I am doing..."

Actually, this is most likely where the problem lies. As in the referenced duplicate, if you reference a property of the ApplicationClass then you'll need to make sure you dereference that property before the garbage collector will tidy up and remove Excel.

So, for instance, copy any data you need to string, int, etc. (or your own internal types based on these base types).

answered Sep 27, 2011 at 12:30

Jeremy McGee

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2 Comments

Nishant Over a year ago

Hi, Thanks for your reply. I just added the some process specific thing am doing to the code above. It is reading all the named ranges and storing it into a Dictionary<string,object> which I am using for other purposes in other part of the code

Jeremy McGee Over a year ago

I've a feeling that the "object" references are storing references to things inside your spreadsheet - so a reference to the source Excel spreadsheet is retained in memory. Instead, create strings (or ints) and store those instead.

Guillaume · Accepted Answer · 2011-09-27 13:49:53Z

0

Try using Marshal.*Final*ReleaseComObject instead of ReleaseComObject. Also call it on your "ApplicationClass excel" instance.

answered Sep 27, 2011 at 13:49

Guillaume

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