Issue with the Visualforce page with the Controller extension

Question

I am trying to create a VF Page on the Case, where I should be able to get the Contact associated with the case. I created a Controller extension like below

public with sharing class CaseControllerExtension {
    
    public Id Case_Id {get;set;}
    
    public CaseControllerExtension(ApexPages.StandardController controller) {
        Case caseObject = (Case)controller.getRecord();
        Case_Id = caseObject.Id;
    }

    public List<Contact> getAssoContact(String caseId){        
        List<Case> Cont = [SELECT ContactId from Case where Id =: Case_Id LIMIT 1];
        List <Contact> conList = new List<Contact>();
        for(Contact con: [SELECT Id, Email, FirstName, LastName, Account.name, MailingCity, MailingState,  MailingCountry,Phone    
                     FROM Contact WHERE Id =: Cont[0].ContactId
                       ORDER BY Id ASC
                       LIMIT 1]){
            conList.add(con); 
        }
      return conList;
}}

And then In the VF Page I am referring the getAssoContact Method so I can reteieve the Contact info like below

<apex:page standardController="Case" extensions="CaseControllerExtension" title="Web Forms" lightningStylesheets="true">

   <apex:tabPanel switchType="client" selectedTab="name1" id="theTabPanel">
        <apex:tab label="Model Generation Services" name="name3" id="tabThree">
            <apex:pageBlock >
            
             <apex:pageBlockTable value="{!AssoContact}" var="con">
                         <apex:column value="{!con.FirstName}"/>      
                         <apex:column value="{!con.LastName}"/>
                      </apex:pageBlockTable>             
            </apex:pageBlock> 
        </apex:tab>
    </apex:tabPanel>
</apex:page>

Here I am getting the error Error: Unknown property 'CaseStandardController.AssoContact' when saving the VF Page component, can anyone please tell me what I am missing here

Answer 1

Getters in Visualforce controllers/extensions can't take any arguments (neither can action methods). There's just no provision for passing arguments to methods like when working with just Apex. The one exception to that that I can think of is if you're using Javascript remoting.

You're getting the required data from the Case_Id property in your extension, and aren't using the caseId argument anyway, so simply remove the argument from the method signature in your extension, and things should work.