Dapper Multi Mapping Result - dapper

Question

I have two classes
public class Customer
{
public int CustomerId { get; set;}
public string CustomerName { get; set; }
}
public class Order
{
public int OrderId { get; set; }
public int CustomerId { get; set; } //BuyerCustomer
public int CustomerSecondId { get; set; } //ReceiverCustomer
public Customer BuyerCustomer { get; set; }
public Customer ReceiverCustomer { get; set; }
}
Here's my query will look like
SELECT a.*, b.*, c.* FROM dbo.PRODUCTS_ORDER a
INNER JOIN dbo.CUSTOMER b ON a.CustomerId=b.CustomerId
INNER JOIN dbo.CUSTOMER c ON a.CustomerSecondId=b.CustomerId
Dapper Implementation..
List<Order> order= null;
order= (List<Order>)dapperconnection.Query<Order, Customer, Customer, Order>(sql,
(order, customer1,customer2) =>
{
order.BuyerCustomer = customer1;
order.ReceiverCustomer = customer2;
return order;
}, splitOn: "CustomerId,CustomerSecondId ");
The result I'm getting is incomplete, only the RecevierCustomer gets populated while the BuyerCustomer doesn't contain any values at all.
It looks like dapper is confused since i used the CustomerId twice in my query.
Is there any workaround with this without having to change my the Customer class?

Answer 1

There are few issues with your class design and Dapper query.
Customer.CustomerName should be string
I would remove CustomerId and CustomerSecondId from Order. They are redundant. You have both Id's in the Customer.
Remove CustomerSecondId from Split.
Below is a working test:
public class Order
{
public int OrderId { get; set; }
public Customer BuyerCustomer { get; set; }
public Customer ReceiverCustomer { get; set; }
}
public class Customer
{
public int CustomerId { get; set; }
public string CustomerName { get; set; }
}
[Test]
public void TestSplitMany()
{
using (var conn = new SqlConnection(#"Data Source=.\sqlexpress;Integrated Security=true; Initial Catalog=foo"))
{
var result =
conn.Query<Order, Customer, Customer, Order>(#"select OrderId = 1, CustomerId = 2, CustomerName = 'Jim', CustomerId = 3, CustomerName = 'Bob'",
(order, buyer, receiver) =>
{
order.BuyerCustomer = buyer;
order.ReceiverCustomer = receiver;
return order;
}, splitOn: "CustomerId").First();
Assert.That(result.BuyerCustomer.CustomerId == 2);
Assert.That(result.ReceiverCustomer.CustomerId == 3);
Assert.That(result.BuyerCustomer.CustomerName == "Jim");
Assert.That(result.ReceiverCustomer.CustomerName == "Bob");
}
}