Procédure : récupérer plusieurs objets à la fois (LINQ to SQL)
Vous pouvez récupérer plusieurs objets dans une requête en utilisant LoadWith.
Exemple
Le code suivant utilise la méthode LoadWith pour récupérer des objets Customer et Order.
Dim db As New Northwnd("c:\northwnd.mdf")
Dim ds As DataLoadOptions = New DataLoadOptions()
ds.LoadWith(Of Customer)(Function(c) c.Orders)
ds.LoadWith(Of Order)(Function(o) o.OrderDetails)
db.LoadOptions = ds
Dim custQuery = From cust In db.Customers() _
Where cust.City = "London" _
Select cust
For Each custObj In custQuery
Console.WriteLine("Customer ID: " & custObj.CustomerID)
For Each ord In custObj.Orders
Console.WriteLine(vbTab & "Order ID: " & ord.OrderID)
For Each detail In ord.OrderDetails
Console.WriteLine(vbTab & vbTab & _
"Product ID: {0}", detail.ProductID)
Next
Next
Next
Northwnd db = new Northwnd(@"northwnd.mdf");
DataLoadOptions ds = new DataLoadOptions();
ds.LoadWith<Customer>(c => c.Orders);
ds.LoadWith<Order>(o => o.OrderDetails);
db.LoadOptions = ds;
var custQuery =
from cust in db.Customers
where cust.City == "London"
select cust;
foreach (Customer custObj in custQuery)
{
Console.WriteLine("Customer ID: {0}", custObj.CustomerID);
foreach (Order ord in custObj.Orders)
{
Console.WriteLine("\tOrder ID: {0}", ord.OrderID);
foreach (OrderDetail detail in ord.OrderDetails)
{
Console.WriteLine("\t\tProduct ID: {0}", detail.ProductID);
}
}
}