How to pass Record ID when StandardController does not contain RecordId

Question

I am working on creating my first wrapper class where I will want to allow users to select from a list of sites (custom object Site__c) and it will relate the site to a quote record through an Associated_Location__c object record.

Right now I am stuck on passing over the AccounId. I was hoping that the controller.getRecord().Id would pass the AccountId into the SOQL query but my query is giving me the old 'List has no rows for assignment to SObject'. I think this has to do with my StandardController being Associated_Location__c as it does not have an AccountId. How can I resolve this issue? Thanks in advance!

public class quoteAssociatedSiteExtension {

public List<assLoc> assLocList {get; set;}
public Quote theQuote;

public quoteAssociatedSiteExtension(ApexPages.StandardController controller) {

    theQuote = [select Id, AccountId from Quote where Id =:controller.getRecord().Id limit 1];
}

public List<assLoc> getAssLoc() {
    if(assLocList == null) {
        assLocList = new List<assLoc>();
        for(Site__c s: [select Id, Name, Account__r.Id from Site__c where Account__r.Id=:theQuote.AccountId limit 10]) {
            assLocList.add(new assLoc(s));
        }
    }
    return assLocList;
}


public PageReference processSelected() {

    List<Associated_Location__c> selectedAssociatedLocations = new List<Associated_Location__c>();

    for(assLoc aLoc: getAssLoc()) {
        if(aLoc.selected == true) {
            selectedAssociatedLocations.add(aLoc.ac);
        }
    }

    System.debug('These are the selected Contacts...');
    for(Associated_Location__c ac: selectedAssociatedLocations) {
        system.debug(ac);
    }
    assLocList=null; 
    return null;
}


public class assLoc {
    public Associated_Location__c ac {get; set;}
    public Site__c st {get; set;}
    public Quote qt {get; set;}
    public Boolean selected {get; set;}

    public assLoc(Associated_Location__c a) {
        ac = a;
        selected = false;
    }

    public assLoc(Site__c s) {
        st = s;
        selected = false;
    }

    public assLoc(Quote q) {
        qt = q;
        selected = false;
    }        
}}

Visualforce Page:

<apex:page standardController="Associated_Location__c" extensions="quoteAssociatedSiteExtension">
<apex:form >
    <apex:pageBlock >
        <apex:pageBlockButtons >
            <apex:commandButton value="Process Selected" action="{!processSelected}" rerender="table"/>
        </apex:pageBlockButtons>
        <apex:pageBlockTable value="{!AssLoc}" var="a" id="table">
            <apex:column >
                <apex:inputCheckbox value="{!a.selected}"/>
            </apex:column>
            <apex:column value="{!a.st.Name}" />
        </apex:pageBlockTable>
    </apex:pageBlock>
</apex:form>

Answer 1

As you mentioned relate the site to a quote record through an Associated_Location__c object record, there will be a field which points to Quote in Associate_Location__c object record. So you should use that field from the controller.getRecord().

Association_Location__c assLoc = (Association_Location__c)controller.getRecord();
theQuote = [select Id, AccountId from Quote where Id =:assLoc.Quote__c limit 1];

But to make the field to be available for the Standard Controller to fetch you need to add it to the Standard Controller before getting the record from the Standard Controller.

controller.addFields(new List<String>{'Quote__c'});

Hope it helps.