Procedure: Veel objecten tegelijk ophalen

U kunt veel objecten in één query ophalen met behulp van LoadWith.

Voorbeeld

De volgende code maakt gebruik van de LoadWith methode om zowel Customer als Order objecten op te halen.

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($"Customer ID: {custObj.CustomerID}");
    foreach (Order ord in custObj.Orders)
    {
        Console.WriteLine($"\tOrder ID: {ord.OrderID}");
        foreach (OrderDetail detail in ord.OrderDetails)
        {
            Console.WriteLine($"\t\tProduct ID: {detail.ProductID}");
        }
    }
}

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

Zie ook

• Query Concepten