C# Excel Addin – Excel does not unload from memory.

Hi,
I’m totally new to C#. I have created a addin with the project wizard in Visual Studio 2008. Everything was going fine until I created a Internet Explorer instance which then uses a event handler (DWebBrowserEvents2_DocumentCompleteEventHandle) to obtain information from the excel application. The code seem to work fine but when I close Excel it goes invisible but I can still see it in my Task Manager.

I suspect it is perhaps a threading issue as I can see that when the event handler fires it does so from a different thread as the main application. Anybody got an idea on how to fix this? I’ll give you some small code snippet from my program.

namespace Myaddin
{
using System;
using Extensibility;
using System.Runtime.InteropServices;
using Office = Microsoft.Office.Core;
using Excel = Microsoft.Office.Interop.Excel;
using IE = SHDocVw;
using System.Windows.Forms;

[GuidAttribute("58163470-8309-4716-AED1-B68D70BF193B"), ProgId("easyXL.Connect")]
public class Connect : Object, Extensibility.IDTExtensibility2
{
public void OnConnection(object Application, Extensibility.ext_ConnectMode ConnectMode, object AddInInst, ref System.Array custom)
{
applicationObject = Application;
addInInstance = AddInInst;
if (Application is Excel.Application)
{
excelApp = (Excel.Application)Application;
if (!CommandBarExist())
{
AddMyCommandBar();
}
}
}
private void doExplore(String queryURL,String qPost)
{
object Missing = System.Reflection.Missing.Value;
m_IExplorer = new IE.InternetExplorer();

…

m_WebBrowser.Visible = true;

…
IE.DWebBrowserEvents2_DocumentCompleteEventHandler DDocumentCompleteE
= new IE.DWebBrowserEvents2_DocumentCompleteEventHandler(OnDocumentComplete);
m_IExplorer.DocumentComplete += DDocumentCompleteE;
}
void OnDocumentComplete(Object o, ref Object ro)
{
Excel.Worksheet activeSheet = (Excel.Worksheet) excelApp.ActiveSheet;
…
m_IExplorer.Quit();

}
}