How to create a condition for apex:inputField value field which gets a boolean expression from a method from controller?

Question

I have the function which returns the boolean value and I want to use it in the VisualForce page in the following way:

<apex:inputField id="reason" value="{!if(!isReason()): Case.Reason__c = 'No Reason' | Case.Reason__c)}" required="true"/>

How can I achieve this?

Answer 1

I would tend to say that you need to set the inputfield value to your custom field "Case.Reason__c", this way it can also be updated manually as you have set it to required.

Then in your constructor set the value based on your logic, or if needed based on an action in the page use an actionfunction to perform the same and actually set it, rerendering it afterwards.

Answer 2

You may need to use addFields to access Reason__c field explicitly inside constructor. You can build logic in constructor like:

public Case cs {get; set;}
public StackExchangeController(ApexPages.StandardController stdController){
    stdController.addFields(new String[]{ 'Reason__c' });
    cs = (Case)stdController.getRecord();
    cs.Reason = !isReason() ? 'No Reason' : cs.Reason__c;
}

Note: Use '' instead of 'No Reason' if you want to unset.

Your visualforce code look like:

<apex:inputField id="reason" value="{!cs.Reason__c}" required="true"/>