Compile Error: Method does not exist or incorrect signature void add(AggregateResult)

Question

My full error message is as follows

Error: Compile Error: Method does not exist or incorrect signature: void add(AggregateResult) from the type List at line 21 column 41

I am working on building a page to represent items in a shipment, that page must show the items picked for the shipment and list their locations in our inventory below each product picked. I am grabbing the information I need from an object called Shipment_Line__c that holds a relation what products have been picked for shipment and the other object is GMBLASERP__Inventory_Movement_Cube__c and it represents where a product is in our inventory. I am needing to match up the two objects based on Project_Task__r.Product_Code__c from Shipment_Line__c and GMBLASERP__Product__c from GMBLASERP__Inventory_Movement_Cube__c.

My controller is as follows:

public class ShipmentInventoryMovements {
    public List<Shipment_Line__c> allShipmentLines { get; set; }
    public List<Shipment_Line__c> displayShipmentLines { get; set; }
    public Map<Id, List<GMBLASERP__Inventory_Movement_Cube__c>> inventoryMap { get; set; }

    public ShipmentInventoryMovements ( ) {
        allShipmentLines = new List<Shipment_Line__c>();
        allShipmentLines = [SELECT Id, Product_ID__c, Shipment__r.Warehouse__r.Name, Quantity__c, Quantity_Filled__c, Project_Task__r.GMBLASERP__Product__r.Name, Project_Task__r.Product_Code__c FROM Shipment_Line__c];

        displayShipmentLines = new List<Shipment_Line__c>(allShipmentLines);
        inventoryMap = new Map<Id, List<GMBLASERP__Inventory_Movement_Cube__c>>();
        for (Shipment_Line__c sl : allShipmentLines) {
            inventoryMap.put(sl.Product_ID__c, new
                    List<GMBLASERP__Inventory_Movement_Cube__c>());
        }
        List<AggregateResult> shipInventory = new List<AggregateResult>([SELECT GMBLASERP__Product__r.id ID, GMBLASERP__Product__r.Name ProdName, GMBLASERP__Location__r.Name LocName, SUM(GMBLASERP__Quantity__c) Sum
                FROM GMBLASERP__Inventory_Movement_Cube__c WHERE GMBLASERP__Product__c IN
                        :inventoryMap.keyset() GROUP BY GMBLASERP__Product__r.id, GMBLASERP__Product__r.name, GMBLASERP__Location__r.name]);

        for(AggregateResult shipLine : shipInventory){
            inventoryMap.get(shipLine.ID).add(shipLine);
        }
    }
}

Answer 1

AggregateResult is not well-documented but it is an object, so you cannot add it to a list of some other object like GMBLASERP__Inventory_Movement_Cube__c. You must iterate through your aggregate result records, extract and cast the values, and create a GMBLASERP__Inventory_Movement_Cube__c record where you assign the values.

For example:

for(AggregateResult shipLine : shipInventory){
  Id theProdId = (Id) shipline.get('ID');
  String theProdName = (String) shipline.get('prodName');
  Integer theSum = (Integer) shipline.get('Sum');
  GMBLASERP__Inventory_Movement_Cube__c theCube = new GMBLASERP__Inventory_Movement_Cube__c(ProdName__c = theProdName, Sum__c = theSum);
  inventoryMap.get(theProdId).add(theCube);
}

See https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/langCon_apex_SOQL_agg_fns.htm for more information.