Resolving the Object variable or With Block variable not set Error in Excel VBA

Описание: Learn how to troubleshoot and fix the `Object variable or With Block variable not set` error in Excel VBA when using class instances.
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This video is based on the question https://stackoverflow.com/q/77919447/ asked by the user 'Jomy' ( https://stackoverflow.com/u/14874405/ ) and on the answer https://stackoverflow.com/a/77919891/ provided by the user 'CHill60' ( https://stackoverflow.com/u/1955044/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Object variable or With Block variable not set Error in VBA

If you're diving into Excel VBA and working with classes, you might encounter the frustrating error message: "Object variable or With Block variable not set." This error typically arises when you try to assign an object to a variable without properly using the Set keyword, especially when you're dealing with class instances.

In this guide, we'll take a closer look at a common scenario where this error occurs, and I'll guide you through the steps to resolve it effectively.

The Problem: When Does This Error Occur?

In the provided code snippet, you're attempting to add a TodoItem instance to a collection of items within a Project class:

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

Why the Error Happens

The error is caused on the following line within the AddItem method of the Project class:

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

Here’s the crucial point: Items is declared as an array of objects, so you must use the Set keyword when assigning an object to it. The correct line should read:

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

The Solution: How to Fix the Error

To resolve this issue, follow these simple adjustments:

Step 1: Update the AddItem Method

Modify the AddItem method in your Project class as follows:

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

Step 2: Review Your Class Declarations

Ensure that both your TodoItem and Project class modules are set up correctly. They should be defined as follows:

TodoItem Class

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

Project Class

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

Additional Tips for VBA Programming

Always Use Set: Remember, in VBA, you must use the Set keyword when assigning object variables.

Debugging: Use Debug.Print or breakpoints in your code to pinpoint where things may be going wrong.

Error Handling: Consider adding error handling in your VBA code to manage unexpected issues gracefully.

Conclusion

By understanding how to correctly use object variables in VBA, you can avoid the dreaded "Object variable or With Block variable not set" error. Make sure to use Set when working with instances of classes and keep an eye on your code structure to maintain clarity. Happy coding!