Trigger validation error message on Submit for Approval (Approval Process)

Question

I have recently encountered an issue, which I do not seem to be able to resolve. I have set up an approval process that fires up if my PickList__c is evaluated true to the following value (or entry criterion): 'New'. When clicking on 'Submit for Approval' the PickList value changes to 'Approved', but prior to that I am running a trigger validation on two mandatory fields on the object (Custom_Field1__c and Custom_Field2__c). Currently, I have some logics on a before insert and before update trigger and I can use add.Error to return the error message on the fields. I would like the error(s) to be thrown on the same page, instead I am redirected to a second screen (titled Choose Approver) that looks like this:

I have a couple of questions:

• Why is it redirecting me to the Choose Approver page?
• Is it possible to return the error on the object? Is this possible to return it on the actual fields?
• Am I correct in including the validation on the before insert and before after trigger?

Ideally, I would like to be able to have the error displayed on the fields, but in second instance I can also consider customising the error on the second screen.

Any suggestion is more than welcome!

Thank you for your help,

Regards,

I.

Answer 1

Yes, you need to add the error logic into the trigger before trying to insert

Something like

boolean b = false;

if(custom_field__c == null){ //test for the error
    custom_field__c.addError('your error message');
    b = true; //set the boolean to true so that update can't happen
}
if(b==false){ //only when there are no errors can you update
    update custom_object__c;
}