Updating a trigger to add another field to be updated

Question

I am hoping someone can guide me. I have created this trigger on a custom object called Trident Contract. It pulled the agent name from the custom object Agent using the Agent Id. Now I need to add the Buyer Agent Office to the trigger. The Buyer Agent Lookup Field was working until I tried to also add the office. Here is my first trigger. Please advise how to add another field lookup. Thank you

trigger BuyAgent on Trident_Contract__c (before insert, before update) {
    Set <String> AgentIDs = new Set <String>();
    for(Trident_Contract__c tc:trigger.new) {
        if(tc.Buyer_Agent_ID__c !=NULL){
            AgentIDs.add(tc.Buyer_Agent_ID__c);
        } 
    }
    //Match Agent ID to Buyer Agent ID
    //Map ID 

    Map<String, Agent__c> Agents = new map <String, Agent__C>();

    for (Agent__c obj: [
        SELECT ID, Agent_ID__c
        FROM Agent__c
        WHERE Agent_ID__c IN :AgentIDs]) {
        Agents.put(obj.Agent_ID__c,obj);
    }
    for(Trident_Contract__c tc : trigger.new) {
        if (Agents.containsKey(tc.Buyer_Agent_ID__c))
            tc.Buyer_Agent_Lookup__c = Agents.get(tc.Buyer_Agent_ID__c).ID;
    }
}

I updated the trigger to the following

trigger BuyAgent on Trident_Contract__c (before insert) {
    Set<String> lagid=new set<string>();
    for(Trident_Contract__c tc :Trigger.new){
        lagid.add(tc.buyer_agent_Id__c);
    }
    Map<String, String>matchid=new Map<String, String>();

    for(Agent__c ag: [
        SELECT Agent_ID__c, Agent_Office__c
        FROM Agent__c 
        WHERE Agent_ID__c IN :lagid]) {
        matchid.put(ag.Agent_ID__c, ag.Agent_Office__c);
    }
    for(Trident_Contract__c tc : Trigger.new) {
        if(matchid.containskey(tc.buyer_agent_ID__c))        
            tc.Buyer_Agent_lookup__c = matchid.get(tc.Buyer_Agent_Lookup__c);
            tc.Buyer_Agent_Office__c = matchid.get(tc.Buyer_Agent_Office__c);
        }
}

But it does not update the Buyer Office Field

Answer 1

The keys to your (updated trigger) map matchId are only values of ag.agent_id__c from the SOQL

As such, the line

tc.Buyer_Agent_Office__c = matchid.get(tc.Buyer_Agent_Office__c);

will never find any entries in matchId unless the Buyer_agent_office__c is the same as the buyer_agent_id__c

Answer 2

I updated the code to the following and get an error message 'Line 1 Map must have exactly 2 arguments'

trigger BuyAgent on Trident_Contract__c (before insert, before update) { Set AgentIDs = new Set (); for(Trident_Contract__c tc:trigger.new){ if(tc.Buyer_Agent_ID__c !=NULL){ AgentIDs.add(tc.Buyer_Agent_ID__c,tc,Buyer_Agent_Office__C);
} } //Match Agent ID to Buyer Agent ID //Map ID

Map Agents = new map ();

for (Agent__c obj: [SELECT ID, Agent_ID__c
                    from Agent__c
                    Where Agent_ID__c 
                    IN: AgentIDs]){Agents.put(obj.Agent_ID__c,obj);}

for(Trident_Contract__c tc : trigger.new) {if (Agents.containsKey(tc.Buyer_Agent_ID__c,tc.Buyer_Agent_Office__C)) tc.Buyer_Agent_Lookup__c = Agents.get(tc.Buyer_Agent_ID__c).ID; tc.Buyer_Agent_Office__c = matchid.get(tc.Buyer_Agent_Office__c); } }