Export (0) Print
Expand All
1 out of 4 rated this helpful - Rate this topic

ObjectQuery<T>.Include Method

Specifies the related objects to include in the query results.

Namespace:  System.Data.Objects
Assembly:  System.Data.Entity (in System.Data.Entity.dll)
public ObjectQuery<T> Include(
	string path
)

Parameters

path
Type: System.String

Dot-separated list of related objects to return in the query results.

Return Value

Type: System.Data.Objects.ObjectQuery<T>
A new ObjectQuery<T> with the defined query path.
ExceptionCondition
ArgumentNullException

path is null.

ArgumentException

path is empty.

Query paths can be used with Entity SQL and LINQ queries.

Paths are all-inclusive. For example, if an include call indicates Include("Orders.OrderLines"), not only will OrderLines be included, but also Orders. For more information, see Shaping Query Results (Entity Framework).

When you call the Include method, the query path is only valid on the returned instance of the ObjectQuery<T>. Other instances of ObjectQuery<T> and the object context itself are not affected.

Because the Include method returns the query object, you can call this method multiple times on an ObjectQuery<T> to specify multiple paths for the query, as in the following example:

// Create a SalesOrderHeader query with two query paths,  
// one that returns order items and a second that returns the  
// billing and shipping addresses for each order.
ObjectQuery<SalesOrderHeader> query =
    context.SalesOrderHeader.Include("SalesOrderDetail").Include("Address");
using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    // Define an object query with a path that returns  
    // orders and items for a specific contact.
    Contact contact =
        context.Contact.Include("SalesOrderHeader.SalesOrderDetail")
        .FirstOrDefault();

    try
    {
        // Execute the query and display information for each item  
        // in the orders that belong to the first contact. 
        foreach (SalesOrderHeader order in contact
            .SalesOrderHeader)
        {
            Console.WriteLine(String.Format("PO Number: {0}",
                order.PurchaseOrderNumber));
            Console.WriteLine(String.Format("Order Date: {0}",
                order.OrderDate.ToString()));
            Console.WriteLine("Order items:");
            foreach (SalesOrderDetail item in order.SalesOrderDetail)
            {
                Console.WriteLine(String.Format("Product: {0} "
                    + "Quantity: {1}", item.ProductID.ToString(),
                    item.OrderQty.ToString()));
            }
        }
    }
    catch (EntitySqlException ex)
    {
        Console.WriteLine(ex.ToString());
    }
    catch (EntityCommandExecutionException ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5 SP1
Did you find this helpful?
(1500 characters remaining)
Thank you for your feedback

Community Additions

ADD
Show:
© 2014 Microsoft. All rights reserved.