Getting values from picklists into visualforce controller

Question

I'm creating a VF page on Opportunity Products where I have an apex:repeat and inside the repeat, I have a picklist that gets it's values from a SOQL query on a related object. I have no problem populating that list but what I can't figure out is how get the values out of every picklist inside the repeat into my controller method and update the original record with those values.

For example, I want Opportunity Product[0] to have its' competitor set as the value from the picklist besides that product name, Opportunity Product[1] with that value etc. Here, competitors are fetched with SOQL query to a custom object. To map the values correctly, that's where I'm stumped. Would using a Map be efficient, where id put into the map the OpportunityProductId and competitor value so I can map the selected value from the picklist to the correct product?

Controller:

Page:

<apex:page controller="VF_compList">
<apex:form >  
<apex:pageBlock >
<table>
    <th>Product name</th><th>Competitor</th>
<div align="left">    
<apex:repeat value="{!products}" var="prods" rendered="true">
<tr>
<div align="left">
 <apex:outputText value="{!prods.name}" id="theValue"/><br/>
</div>
<div align="right">
<apex:selectList id="dropdown"  multiselect="false" size="1"> 
<apex:selectOptions value="{!Competitors}">
</apex:selectOptions>
</apex:selectList>
</div>
</tr>
</apex:repeat>
    </div>
    </table>
</apex:pageBlock>
<apex:commandButton action="{!submit}" id="theButton"/>
</apex:form>
</apex:page>

controller:

public class VF_compList {


public VF_compList(){}

public Id gId = ApexPages.currentPage().getParameters().get('gId');


Opportunity o = [SELECT id from Opportunity where Id =:gId];

Map<Id,String> prodMap = new Map<Id,String>();



public List<SelectOption> comps {get;set;} 
public List<OpportunityLineItem> olist {get;set;}
public List<Opportunity_Competitor__c> competitorsList {get;set;}
String[] tempstring {get;set;}

public void setCompetitorsOnKeyup(){

}

public List<SelectOption> getCompetitors(){
system.debug('gId is: '+gId);
competitorsList = [SELECT Name, Competitor__r.Name from 
Opportunity_Competitor__c where Opportunity__c =:o.Id];
List<SelectOption> values = new List<SelectOption>();
for(Opportunity_Competitor__c a:competitorsList){
    SelectOption b = new 
SelectOption(a.Competitor__r.Name,a.Competitor__r.Name);
    values.add(b);
    //comps.add(b);
}    
return values;

}

public List<OpportunityLineItem> getProducts(){
olist = [SELECT Id, Name,txCompetitors__c from OpportunityLineItem where 
OpportunityId =:o.Id];
return oList;

}

public void submit(){
    for(OpportunityLineItem e:olist){
        //e.txCompetitors__c = ?
    }
}   

}

Answer 1

In all but the most unusual scenarios, it is generally advisable to put the ID value for the first parameter of your SelectOption. This gives you the automatic mapping you're looking for without any extra effort:

competitorsList = [SELECT Name, Competitor__c, Competitor__r.Name from 
Opportunity_Competitor__c where Opportunity__c = :o.Id];
List<SelectOption> values = new List<SelectOption>();
for(Opportunity_Competitor__c a:competitorsList){
    SelectOption b = new 
SelectOption(a.Competitor__c,a.Competitor__r.Name);
    values.add(b);
    //comps.add(b);
}    
return values;

---

<apex:selectList value="{!lineitem.txCompetitors__c}" id="dropdown"  multiselect="false" size="1"> 

---

Please note that getCompetitors right now is essentially a query inside of a loop, and may cause your code to crash from too many SOQL queries. At minimum, you should cache the results to avoid this problem:

transient List<SelectOption> competitorsOptions;
public List<SelectOption> getCompetitors(){
    if(competitorsOptions == null) {
        competitorsList = [SELECT Name, Competitor__c, Competitor__r.Name from 
        Opportunity_Competitor__c where Opportunity__c = :o.Id];
        competitorsOptions = new List<SelectOption>();
        for(Opportunity_Competitor__c a:competitorsList){
            SelectOption b = new 
                SelectOption(a.Competitor__c,a.Competitor__r.Name);
            competitorsOptions.add(b);
        }
    }
    return values;
}

---

Also, you're going to need to initialize your list of opportunity line items so that you can edit them. This answer presumes that you've changed your code so that you can bind your inputs to the line items you're creating.