[RESOLVED] Excel process spawned from VB will not go away

[campster]

I'm using VB to create Excel templates and everything appeared to be working fine until I was stepping though some code today with my Task Manager open. I noticed that I had numerous instances of Excel open that should not be. This is the code that is being called to close the process:

Public Sub Close()
    Try
      If Not oExcel Is Nothing Then
        oExcel.DisplayAlerts = False
        oExcel.Quit()
        oExcel = Nothing
        GC.Collect()
      End If
    Catch ex As Exception
      MessageBox.Show("TemplateReader.Close: " & ex.Message.ToString)
    End Try
  End Sub

When stepping through this code I am hitting the exception after the execution of the GC but the message box does not appear so the the using thinks that everything is fine.

When I close my applicataion all of the Excel processes shown by the Task Manager close as well. Can anyone help provide an explanation as to why the Excel instances do not close until the application closes?

[Jenner]

What is oExcel defined as? Is it a Process object?

[ForumAccount]

You need to release the COM object:

System.Runtime.InteropServices.Marshal.ReleaseComObject(oExcel)
            oExcel = Nothing

[campster]

Thanks for the quick replies.

Unfortunatley, releasing the object did not close the prosess.

Here's the way I'm defining OExcel and how the file is opened.

Private oExcel As Excel.Application
 
  Public Function Open() As Boolean
    Try
      oExcel = New Excel.Application
      oExcel.Workbooks.Open(Filename:=Me.input)
 
      Try
        oSht = CType(oExcel.Workbooks(1).Worksheets("control"), Excel.Worksheet)
      Catch ex As Exception
        ' ignore exception and throw one that is more meaningful
        If oSht Is Nothing Then
          Throw New System.Exception("Invalid Template Format: No Control Sheet")
        End If
      End Try
 
     ' Populate some cells.
 
      oExcel.Visible = Me.visible
      Return True
 
    Catch ex As Exception
      MessageBox.Show("TemplateReader.Open: " & ex.Message.ToString)
      Return False
    End Try

[ForumAccount]

It works for me. I have a class for Excel which implements IDispose and this is my dispose sub:

Public Sub Dispose() Implements IDisposable.Dispose
            _ExcelWB.Close(False)
            _ExcelApp.Quit()
            System.Runtime.InteropServices.Marshal.ReleaseComObject(ExcelApp)
            _ExcelWB = Nothing
            _ExcelApp = Nothing
            GC.SuppressFinalize(Me)
        End Sub

This clears the process for me.

[campster]

Looking at your code lead me in the right direction, thanks.

I was was defining oSht as an Excel worksheet and not releasing it. Here's my final code. Still hitting the exception without displaying the message box but I'm not worried about that (for today).

Public Sub Close()
    Try
      If Not oExcel Is Nothing Then
        oExcel.DisplayAlerts = False
        oExcel.Quit()
        System.Runtime.InteropServices.Marshal.ReleaseComObject(oSht)
        System.Runtime.InteropServices.Marshal.ReleaseComObject(oExcel)
        oSht = Nothing
        oExcel = Nothing
        GC.Collect()
      End If
    Catch ex As Exception
      MessageBox.Show("TemplateReader.Close: " & ex.Message.ToString)
    End Try
  End Sub