Validating Mandatory Fields During Purchase Requisition Workflow Approval in D365F&O

Hi everyone!

I recently worked on a requirement to validate mandatory fields (including a custom field) during the Purchase Requisition workflow approval in Dynamics 365 Finance and Operations (D365F&O).

To achieve this, I worked with the standard class:

This class extends the base and is used as the event handler for Purchase Requisition workflows in D365F&O.

The key point here is that includes a method, which is automatically triggered during the workflow approval process.

To implement the validation logic for mandatory (including custom) fields, I created a Chain of Command (CoC) extension of the method.

Here's the sample code:

With this code, if the Vendor Account field is empty during workflow approval, the system throws a validation error and stops the approval process. You can extend this to validate multiple custom fields based on business rules.