Visualforce : Lookup field Event

Question

I have a lookup field declared as below:

<apex:inputfield value="{!Product2.Opportunity__c}" id="prodoppr"/> 

wish to know how to add or handle event for this lookup field? When there is a change in the value I want to trigger method to perform certain validation and upate other fields....how can i achieve this? please any inputs?

Answer 1

You can use apex:actionSupport to listen for changes and respond accordingly. For example:

<apex:inputfield value="{!Product2.Opportunity__c}" id="prodoppr">
    <apex:actionsupport event="onchange" action="{!validateandupdate}" reRender="form" />
</apex:inputfield>

If you want to do client-side validation, you can also use apex:inputField's onchange attribute to support listening for changes to the lookup field.

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Edit: The action attribute is used to determine the function to call. So, in this example, the function is named validateAndUpdate, which would look like this:

public void validateAndUpdate() {
    if(...) { // Some validations
        ApexPages.addMessage(...);
    } else {
        update someRecords;
    }
}

Appropriate error handling should also be part of such a function to avoid partial transactions by way of Database.setSavePoint and Database.rollback.