While Lightning Web Components (LWC) are the modern standard for Salesforce UI development, thousands of organizations still maintain and build upon complex Visualforce pages for internal data-entry tools. One of the most common—and challenging—requirements is creating a single, unified screen where users can dynamically add multiple parent records (like Accounts) and multiple child records (like Contacts) at the same time before hitting save. In plain words: To let users click an "Add Row" button for both parent and child records on a single Visualforce page, you must use "nested wrapper classes" in your Apex controller. These wrappers tie the records together in the server's memory, so when the user adds or deletes a specific row, Salesforce knows exactly which data to update without losing their inputs.
Apex Development