How do I kill a process that doesn't have any windows in VB.net? - vb.net

Question

I am new to VB.net and I am trying to write a forms app that works with Autodesk Inventor.
Unfortunately, every time I close Inventor, the "Inventor.exe" process still stays. I didn't realize this while debugging and I only realized this when I checked the task manager after the whole system started to lag.
Killing every process with the same name is fairly simple, but the issue is that the end user might have separate documents open in another Inventor window. So I need to write a function that only kills the Inventor processes that don't have a window open.
Public Class Form1
Dim _invApp As Inventor.Application
Dim _started As Boolean = False
Public Sub New()
' This call is required by the designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
Try
_invApp = Marshal.GetActiveObject("Inventor.Application")
Catch ex As Exception
Try
Dim invAppType As Type = _
GetTypeFromProgID("Inventor.Application")
_invApp = CreateInstance(invAppType)
_invApp.Visible = True
'Note: if you shut down the Inventor session that was started
'this(way) there is still an Inventor.exe running. We will use
'this Boolean to test whether or not the Inventor App will
'need to be shut down.
_started = True
Catch ex2 As Exception
MsgBox(ex2.ToString())
MsgBox("Unable to get or start Inventor")
End Try
End Try
End Sub
Another section where I start a process, which is a specific 3D model file.
Public Sub SaveAs(oTemplate As String)
'define the active document
Dim oPartDoc As PartDocument = _invApp.ActiveDocument
'create a file dialog box
Dim oFileDlg As Inventor.FileDialog = Nothing
Dim oInitialPath As String = System.IO.Path.GetFullPath("TemplatesResources\" & oTemplate)
_invApp.CreateFileDialog(oFileDlg)
'check file type and set dialog filter
If oPartDoc.DocumentType = kPartDocumentObject Then
oFileDlg.Filter = "Autodesk Inventor Part Files (*.ipt)|*.ipt"
ElseIf oPartDoc.DocumentType = kAssemblyDocumentObject Then
oFileDlg.Filter = "Autodesk Inventor Assembly Files (*.iam)|*.iam"
ElseIf oPartDoc.DocumentType = kDrawingDocumentObject Then
oFileDlg.Filter = "Autodesk Inventor Drawing Files (*.idw)|*.idw"
End If
If oPartDoc.DocumentType = kAssemblyDocumentObject Then
oFileDlg.Filter = "Autodesk Inventor Assembly Files (*.iam)|*.iam"
End If
'set the directory to open the dialog at
oFileDlg.InitialDirectory = "C:\Vault WorkSpace\Draft"
'set the file name string to use in the input box
oFileDlg.FileName = "######-AAAA-AAA-##"
'work with an error created by the user backing out of the save
oFileDlg.CancelError = True
On Error Resume Next
'specify the file dialog as a save dialog (rather than a open dialog)
oFileDlg.ShowSave()
'catch an empty string in the imput
If Err.Number <> 0 Then
MessageBox.Show("Any changes made from here will affect the original template file!", "WARNING", MessageBoxButtons.OK, MessageBoxIcon.Warning, MessageBoxDefaultButton.Button1, MessageBoxOptions.ServiceNotification)
ElseIf oFileDlg.FileName <> "" Then
Dim MyFile As String = oFileDlg.FileName
'save the file
oPartDoc.SaveAs(MyFile, False)
'open the drawing document
System.Diagnostics.Process.Start(oInitialPath & ".idw")
Dim oFinalPath As String = oPartDoc.FullFileName
MessageBox.Show(oFinalPath, "", MessageBoxButtons.OK, MessageBoxIcon.None, MessageBoxDefaultButton.Button1, MessageBoxOptions.ServiceNotification)
MessageBox.Show("Loaded", "", MessageBoxButtons.OK, MessageBoxIcon.None, MessageBoxDefaultButton.Button1, MessageBoxOptions.ServiceNotification)
Dim oDrawingDoc As DrawingDocument = _invApp.Documents.ItemByName(oInitialPath & ".idw")
'oDrawingDoc.SaveAs()
End If
End Sub
Any help is appreciated.
Thanks

Answer 1

At the end on your form, probably FormClosed, add the following:
Private Sub Form1_FormClosed(sender As Object, e As FormClosedEventArgs) Handles Me.FormClosed
If (_invApp Is Nothing) Then Return ' if empty, then no action needed
_invApp.Quit()
Marshal.ReleaseComObject(_invApp)
_invApp = Nothing
System.GC.WaitForPendingFinalizers()
System.GC.Collect()
End Sub
This should make .NET release and properly dispose the COM Object for Inventor.
And consider declare the Inventor variable and assign Nothing/null, it's safer (avoid mistakes)
Dim _invApp As Inventor.Application = Nothing