Invalid Cast Exception Error When Running VB Code

[Anonymous]

Using VB2010 Express to practice writing code to run things in Inventor 2012.  I am an extreme beginner at this, and I am trying out a simple program that opens up Inventor, and when you click a button, it will open up the filename listed in the subroutine.  I have attached a .jpg of my code.  The program will open Inventor, and open the file, but as soon as the file is finished loading and displays on the screen, it throws the error you see in the .jpg.  Any clues as to what I'm doing wrong?

[ekinsb · Accepted solution]

You've typed the variable to be a PartDocument but you're opening an assembly.  That's what it's complaining about.  The Open call is succeeding but then when it tries to assign the opened document to your variable it's failing.

[Anonymous]

Oh geez, that was staring me right in the face  🙂

Huge thanks!!