Connecting to inventor with Vb.net

[MechMachineMan]

What am I doing wrong here/how do I get this properly working?

Imports Inventor
Imports System.Runtime.InteropServices

Public Class InventorApp
	Property oApp As Inventor.Application
	
	Public Shared Sub ConnectToInv()
    	Try
       		oApp =  Marshal.GetActiveObject("Inventor.Application")
    	Catch ex As Exception
        	MessageBox.Show("Cannot connect to Inventor")
        	Exit Sub
    	End Try
	End Sub
End Class

Sub Main()
	InventorApp.ConnectToInv
	Dim oDoc As Document
	oDoc = InventorApp.oApp.ActiveDocument
	
	MsgBox(oDoc.FullFileName)
	
	'Dim inputList As New List(Of String)

	
	'SortBOM(inputList)
End Sub

[MechMachineMan · Accepted solution]

Guess I figured it out:

Imports System
Imports System.Type
Imports System.Activator
Imports Inventor
Imports System.Runtime.InteropServices

'Need to make this public so it can be used in other classes
Public Class CL_InventorApp

        'Need to make this public so it can be used in other classes
        'InventorInstance will be the accessible object within the    
        'CL_InventorApp class whenever we create access to the class
	Dim Public InventorInstance As Inventor.Application
	Dim _started As Boolean
	
         'When you call New CL_InventorApp, this sub gets invoked.
	Public Sub New()
		'Everything in this sub is fluff stolen from 
                'elsewhere with variable names changed to suit my purposes
		Try
       		InventorInstance =  Marshal.GetActiveObject("Inventor.Application")
 			
		Catch ex As Exception
			   Try     
					Dim invAppType As Type = GetTypeFromProgID("Inventor.Application")     
					
					InventorInstance = CreateInstance(invAppType)     
					InventorInstance.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") 
						Exit Sub
					End Try
		End Try
	End Sub
End Class

Public Sub Main()

          'Need to create access to the class the app was opened in, so ref
          ' the CL_InventorApp. oInv_App is what we use to access that class.
	Dim oInv_App As New CL_InventorApp
	MsgBox("All is good")
	
	MsgBox(oInv_App.InventorInstance.ActiveDocument.FullFileName)
	
End Sub