Final answer:
The addError() method in Salesforce's Apex is used to add a custom error message to a field on an sObject. You reference the field using dot notation and then call addError() with the error message string as the argument. This prevents the record from saving if the error condition is met.
Step-by-step explanation:
The addError() method is used in Salesforce's Apex programming to add custom error messages to the fields of an sObject. This method can be utilized in a number of scenarios such as validation rules, triggers, or classes to display user-friendly error messages when data does not meet certain criteria or to prevent certain operations from happening on a record.
To apply the addError() method to a specific field on an sObject, you would use dot notation to reference the field, then call the addError() method with the desired error message string. Here's an example code snippet:
Account myAccount = new Account(Name = 'Test Account');
myAccount.Phone.addError('The phone number format is invalid.');
In this example, we are adding a custom error message to the 'Phone' field of an Account record. When the record is attempted to be saved, the system will display the custom error message, preventing the save operation if the condition that triggers the error is met.
.