Updating OpportunityLineItem fields issue

Question

I've written a trigger that updates some fields on the Opportunity Product object with Product values when the Opportunity reaches 95% probability.

The trigger works when I edit and save the OpportunityLineItem but does not update if I just change the Opportunity stage to 95%.

What adjustments do i need to make so that the fields are updated as soon as the Opportunity reaches 95%?

trigger OppProductNetValue on OpportunityLineItem (before insert, before update) {

      Map<Id,Opportunity> parentopps = new Map<Id, Opportunity>();

        Set<Id> pbeIds = new Set<Id>();

            for(OpportunityLineItem oli : trigger.new) {
            if(oli.PriceBookEntryId != null){
              pbeIds.add(oli.PriceBookEntryId);
               parentopps.put(oli.OpportunityId,null);
             }
           }
        Map<id, PriceBookEntry> pbeMap = new Map<id, PriceBookEntry>(
             [SELECT id, Product2.id, Product2.True_Price__c
                     FROM PriceBookEntry WHERE id in :pbeIds]);
                     parentopps.putall([select Id, Probability, Order__c from Opportunity where Id in      :parentopps.keyset()]);

                   for(OpportunityLineItem oli : trigger.new) {
               if((pbeMap.containsKey(oli.PriceBookEntryId))&& (parentopps.get(oli.OpportunityId).Order__c == 'Sales Line')&&  (parentopps.get(oli.OpportunityId).Probability == 95)){
                   oli.Net_Value__c = pbeMap.get(oli.PriceBookEntryId).Product2.True_Price__c*oli.Quantity;      
                     }else{
              oli.Net_Value__c = (1-oli.Discount*.01)*(oli.Quantity)*(oli.UnitPrice);
          }  
    }
 }

Answer 1

You need to write a trigger for Opportunity. The trigger you wrote is for OLI and thus will not fire when an Opportunity is updated

Answer 2

You can use an IF( ) Function to accomplish this.

IF( Opportunity.Probability > 0.95,  PricebookEntry.Product2.CustomField1__c , "")

Please note, decimals require a 0 before the decimal to work Salesforce.