Missing Properties and Methods from Type Library Object in LabVIEW

Updated Nov 20, 2023

Reported In

Software

  • LabVIEW

Operating System

  • Windows

Issue Details

Every time I launch LabVIEW to open a VI that uses a type library (*.tlb file), all of the items from the property and invoke nodes linked to an object from the type library are missing.
 
no properties
For some libraries I need to browse to the type library file and select it again from the ActiveX Automation Open reference constant to be able to run my code.This only happens when opening the VI in a 32-bit installation of LabVIEW, the 64-bit version shows the properties and methods correctly.

For other libraries, I am not able to find it in LabVIEW when browsing the type libraries available on the computer.

Solution

This issue can be seen due to a missing entry in the Windows Registry for the object library that is presenting the reported behavior, or that the application that provides the type library has a different bitness than the LabVIEW version you are using.

Make sure the application you are trying to control, such as Microsoft Outlook, has the same bitness of the LabVIEW version being used.

A possible workaround is to manually create an entry for the type library in the registry, following these steps:

WARNING: Inappropriate changes to the Windows Registry can cause unexpected behavior in the Operating System. To safeguard against such an event, you should backup your existing Registry by selecting File>>Export after launching the Registry Editor and before making any changes.
 
1. In the Windows search bar, type regedit and press <Enter> to open the Registry Editor.
2. Navigate to Computer\HKEY_CLASSES_ROOT\TypeLib.
 
step1.png

3. Using <Ctrl-F>, search for the type library object. You should see something similar to the following:
 
step 2.png
 
  • Notice that when you expand the keys as shown above, there is a key called "win64", but not one called "win32".
4. Create a new key and copy the contents in the existing key to the newly created one. The content of the key is the path to the type library file.
 
step3.png
  • To create the new key, you can right-click the key named "0" select New>>Key, and name it "win32".
  • You can copy the contents from the "win64" key by opening it then right-click its entry, select Modify and copy the text in the Value data parameter. Click on Cancel to close the window.
  • To paste the value, go to the newly created key and right-click its entry to Modify it and paste the value in the Value data parameter, the result should look similar to the image above.
5. Close all LabVIEW windows.

6. After launching LabVIEW again, the properties or methods appear correctly.
 
result

Additional Information

The bitness of the registry entry needs to match the bitness of the LabVIEW version being used. That is why the issue can be seen in LabVIEW 32-bit if the type library creates an entry for 64-bit only.

If you notice any unexpected side effects after creating the manual entry, you can remove the created key in the Windows Registry by right-clicking it and selecting Delete.