Attach existing opportunity to lead during lead conversion through Apex

Question

I am trying to convert a lead and then attach an existing opportunity on it.

Below is my sample piece of code.

Public static void convertLeadUponDealApproval(String LeadRec,Id OpptyId){ 
    Id accountId;
    Id LeadId;
    Id ownerId;
    Lead LeadRecd;
    Opportunity opp;
    list<lead> LstLeadRecd= new list<lead>();
    if(OpptyId != null){
        opp = [Select id, accountId,ownerId from Opportunity where Id =: OpptyId limit 1];
        accountId = opp.accountId;
        ownerId = opp.OwnerId;
    }    

    if(LeadRec != null && LeadRec != ''){
       LstLeadRecd = [select id,Lead_ID__c,Custom_ConvertedOpportunityId__c from lead where isConverted= false and Lead_ID__c = : LeadRec limit 1];
       if(!LstLeadRecd.isEmpty()){
       LeadRecd=LstLeadRecd[0];        
       LeadId = LeadRecd.Id;
       LeadRecd.Custom_ConvertedOpportunityId__c = opp.Id;
       LeadRecd.Ignore_Workflow__c = true;
       update LeadRecd;
        }    
    }

    if(!LstLeadRecd.isEmpty()){
    Database.LeadConvert lc = new database.LeadConvert();
    lc.setDoNotCreateOpportunity(true);
    lc.setLeadId(LeadId);
    lc.setAccountId(accountId);
    //lc.setOpportunityName(OpptyId);  //I am unable to do this.Are there any alternative? 
    lc.setConvertedStatus('4 New Opportunity'); 
    lc.setownerId(ownerId);
    Database.LeadConvertResult lcr = Database.convertLead(lc);
    } 
 }

Answer 1

You're absolutely correct. Your only two choices are to create a new opportunity or not. You can't link the converted lead to an existing opportunity in a way that it will appear on the "lead has been converted" screen.

Answer 2

This may not be exactly what you are looking for, but I was able to do something similar, and you may be able to adapt it to your needs.

        //update the leads
        //LeadConvert can only handle 100 records at a time
        if(!leadConvertList.isEmpty()){
            //Update Opp close date with map of data
            Map<id,id> leadOppMap = new Map<id,id>();
            Map<id,id> leadContMap = new Map<id,id>();
            List<Opportunity> updateOppList = new List<Opportunity>();

            //convert the leads
            for(Integer i = 0; i <= leadConvertList.size()/100 ; i++){
                list<Database.LeadConvert> tempList = new list<Database.LeadConvert>();
                Integer startIndex = i*100;
                Integer endIndex = ((startIndex+100) < leadConvertList.size()) ? startIndex+100: leadConvertList.size();
                for(Integer j=startIndex;j<endIndex;j++){
                    tempList.add(leadConvertList[j]);
                }
                //system.debug('tempList conversion = ' + tempList);
                Database.LeadConvertResult[] lcrList = Database.convertLead(tempList, false);
                for(Database.LeadConvertResult lcr : lcrList){
                    if(!lcr.isSuccess()){
                        //log internal error                            

                        //revert conversion checkboxes
                        Lead revLead = new Lead(id = lcr.getLeadId(), Convert_No_Opp__c = false, Convert_with_Opp__c = false);
                        revertList.add(revLead);
                    } else {
                        leadOppMap.put(lcr.getLeadId(),lcr.getOpportunityId());
                        leadContMap.put(lcr.getLeadId(),lcr.getContactId());
                    }
                }
                if(revertList.size()>0){update revertList;}
            }

            //after convert, update any opportunities
            for(Lead l: givenLeads){
                if(leadOppMap.containsKey(l.Id) && leadOppMap.get(l.Id)!=null){
                    updateOppList.add(new Opportunity(id = leadOppMap.get(l.Id),
                                                      CloseDate = l.ExpectedStartDate__c,
                                                      name = l.LastName + ' New Enrollement',
                                                      contact__c = leadContMap.get(l.Id),
                                                      type = 'LIS',
                                                      StageName = 'Enrolled'
                                                      //record type
                                                     ));                    
                }
            }

            //update opportunities
            if(updateOppList.size()>0){
                //System.debug('Inserting updateOppList: ' + updateOppList);
                Database.SaveResult[] oppDML = Database.update(updateOppList,false);
                for(Database.SaveResult sr: oppDML){
                    if(sr.isSuccess() && !Test.isRunningTest()){
                        System.debug('Successfully updated opportunity ' + sr.getId() + ' which was created because of the converted lead.');
                    } else if(!sr.isSuccess() || Test.isRunningTest()){
                        //log error
                    }                    
                }
            }