Resolving Run-time Error '438': Accessing Custom Objects in a VBA Collection

Learn how to fix the run-time error '438' in VBA when accessing custom objects added to a collection in a custom class. Follow our step-by-step guide!
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Resolving Run-time Error '438': Accessing Custom Objects in a VBA Collection

VBA, or Visual Basic for Applications, allows developers to create custom classes that can be very useful when designing applications. However, sometimes you may encounter frustrating errors, like the run-time error '438'. This error typically arises when attempting to access a custom object that has been added to a collection within another custom class. In this guide, we will explore the problem and provide a clear solution.

The Problem

Suppose you have a custom class, List, defined to hold various items, including other List objects. When you add a List object directly to a collection in a Sub, everything works perfectly. For example, the following code runs without issues:

[[See Video to Reveal this Text or Code Snippet]]

However, if you attempt to add a List object to another List object and later retrieve it using a method like GetAt, a run-time error '438' is returned. Here’s the problematic code:

[[See Video to Reveal this Text or Code Snippet]]

Why Does This Happen?

The issue arises because VBA requires a specific way to retrieve objects that have been stored in collections. When you add objects to your custom class's internal collection, the GetAt method must be able to identify and return object types correctly. If it cannot, you will see the '438' error indicating that the object doesn't support this property or method.

Interestingly, this problem does not occur with primitive values (like strings or numbers), as they do not require a special retrieval method.

The Solution

To fix the error, you’ll need to adjust the code in your List class as follows:

Step 1: Update the GetAt Method

You need to modify the GetAt method to handle both object types and primitive values correctly. Here’s how you can do it:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Test the Code

Make sure you create a Sub to test the new functionality. Here’s an example of how to do this:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By updating your GetAt method to properly handle both object and primitive types, you can avoid the run-time error '438' when accessing your custom objects in VBA. Implement this change in your code, and your applications should function smoothly without hiccups.

Feel free to test out this solution, grasp its significance, and provide any feedback you may have!