How to Type Cast Sobject List to custom object List in Apex to access custom object fields

Question

Let's consider the below scenario:

I have a scenario to type cast sObjectList into the List<customObject__c> so that I can access customObject fields and store it into the following:

String customValue1 = '';
String customValue2 = '';
String customValue3 = '';
String customValue4 = ''; 

Based on the recordId I'm fetching the targetobjectApi name and getting the fields to query on this object from the custom metadata created.

After constructing the SOQL - String soqlQuery = 'SELECT ' + fields + ' FROM ' + targetObjectApiName; // It returns the sobject List

Now in the switch case I have to write a logic to convert this sobject list returned into customObject__c list so that I can access fields on the customObject__c.

Please find the code below:

String recordId = 'a2r540000014DwFAAU'; 

//Create String to store the query 
String query = ''; 
String fields = ''; 

//Create String to store custom Object values  
String customValue1 = '';
String customValue2 = '';
String customValue3 = '';
String customValue4 = ''; 


//Create List to Store customObject__c 
List<customObject__c> customObjectList = new List<customObject__c>(); 


Id newId = Id.valueOf(recordId);
String targetObjectApiName =  newId.getSObjectType().getDescribe().getName();

System.debug('targetObjectApiName-------->' + targetObjectApiName);

//Get Fields From Custom Metadata
List<customMetadata__mdt> customMetadataRecords = [SELECT Field__c, Object__c FROM customMetadata__mdt WHERE Object__c = :targetObjectApiName]; 
System.debug('customMetadataRecords---------->' + customMetadataRecords); 

if(customMetadataRecords!=null && !customMetadataRecords.isEmpty()){
    for(customMetadata__mdt mdtObj: customMetadataRecords){ 
        fields = mdtObj.Field__c; 
        System.debug('fields---------->' + fields);
    }
}

//Construct SOQL Query 
String soqlQuery = 'SELECT ' + fields + ' FROM ' + targetObjectApiName; 
System.debug('soqlQuery----------->' + soqlQuery);

List<sObject> sObjectList = Database.query(soqlQuery); 
System.debug('sObjectList--------> ' + sObjectList);

//Store Values 
if(sObjectList!=null && !sObjectList.isEmpty()){
    switch on targetObjectApiName {
            when 'customObject__c' {    
               //Need help here in typecasting
               customObjectList = (List<customObject__c>) sObjectList; 
               //Need help here in storing customField__c values 
               customValue1 = customObjectList[0].customField1__c;
               customValue2 = customObjectList[0].customField2__c;
               customValue3 = customObjectList[0].customField3__c;      
               customValue4 = customObjectList[0].customField4__c;
              
            }
            when else {      
                return 'Other Option';
            }
        }//End Switch 
}

Any kind of help is appreciated. Thank you 

Answer 1

You can just statically declare the type in this switch block. Keeping it dynamic once you have gotten this far adds little (if any) value.

switch on targetObjectApiName {
    when 'customObject__c' {
        List<CustomObject__c> concreteRecords = sObjectList;
        CustomObject__c record = concreteRecords[0];
        customValue1 = record.CustomField1__c;
        // etc.
    }
}

Answer 2

You do not need to cast the records at all. The SObject base class provides the get method that allows retrieval of a field value (as Object, which can be converted to a string using String.valueOf, for example). As long as you can get the field API names from your custom metadata, you can pass them in to this get method to find the field values.

You can, of course, use the object type name to retrieve the relevant custom metadata record(s) too.

See the SObject documentation for more detail.