Not able to get the UnitPrice using MAP

Question

I have a Custom object Product_Quantity__c and it has a lookup field for Product, when user going to select any of the Product from that lookup field in Visualforce page then what i need is that product's List Price will auto populate

However, i doing same thing for Product's ProductCode & description and it's working fine

i know ProductCode and Description are info of the Direct Product but List Price is info of the Product's PriceBookEntry

Can anyone tell me where i need to change in my code or what i have done wrong ?

Apex class :

mapPricebookEntryIdToPricebookEntry = new Map<Id, PricebookEntry>();
PriceBookEntry = new PricebookEntry();

public void retrieveproductInfo() {
    for(Product2 product : [SELECT Id, ProductCode, Description FROM Product2]) {
        mapProductIdToProduct.put(product.Id, product);
        mapPricebookEntryIdToPricebookEntry.put(product.Id, PriceBookEntry);
        system.debug('====MAP====='+mapPricebookEntryIdToPricebookEntry);
    }
    if(PrdQuantity.Product__c != Null){
        this.partNumber = mapProductIdToProduct.get(PrdQuantity.Product__c).ProductCode;
        this.Description = mapProductIdToProduct.get(PrdQuantity.Product__c).Description;
        this.ListPrice = mapPricebookEntryIdToPricebookEntry.get(PrdQuantity.Product__c).UnitPrice;
    }
}

Debug :

Answer 1

You need to add a separate query to get PriceBookEntry.

for(PriceBookEntry entry : [SELECT Id, Product2Id, UnitPrice FROM PriceBookEntry]) { 
    mapPricebookEntryIdToPricebookEntry.put(entry.Product2Id, entry); 
    system.debug('====MAP====='+mapPricebookEntryIdToPricebookEntry); 
}