Update options on a Muli-Select Custom field with Apex Code

Question

I have a case where I need to update the options in a multi-select custom field from an Apex Trigger. Is this possible?

My full use case is on a Create/Update of a Custom Object, if a pre-defined condition is met, update a particular custom field (on another Custom Object) with an additional multi-select option.

-Clarification-

I am looking to add options to a select list custom field, not just select values that already exist in the select list.

Answer 1

Yes it is possible. The options are semicolon (;) delimited. You will first have to make sure the field doesn't already contain the option you are trying to add. Also make sure at least one option is selected before performing any such checks.

if (String.isNotBlank(triggerRecord.Multi_Select__c))
{
    Set<String> selectedOptions = new Set<String>(triggerRecord.Multi_Select__c.split(';'));
    if (!selectedOptions.contains(optionToAdd))
        triggerRecord.Multi_Select__c += ';' + optionToAdd;
}

Honestly though, unless you have a Validation Rule acting on this field, you should just use Process Builder.