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.NET Framework 3.5
 Include Method
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This page is specific to
Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:
.NET Framework Class Library
ObjectQuery<(Of <(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)
Visual Basic (Declaration)
Public Function Include ( _
    path As String _
) As ObjectQuery(Of T)
Visual Basic (Usage)
Dim instance As ObjectQuery
Dim path As String
Dim returnValue As ObjectQuery(Of T)

returnValue = instance.Include(path)
C#
public ObjectQuery<T> Include(
    string path
)
Visual C++
public:
ObjectQuery<T>^ Include(
    String^ path
)
JScript
public function Include(
    path : String
) : ObjectQuery<T>

Parameters

path
Type: System..::.String
Dot-separated list of related objects to return in the query results.

Return Value

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

path is nullNothingnullptra null reference (Nothing in Visual Basic).

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<(Of <(T>)>). Other instances of ObjectQuery<(Of <(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<(Of <(T>)>) to specify multiple paths for the query, as in the following example:

Visual Basic
' 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.
Dim query As ObjectQuery(Of SalesOrderHeader) = _
    context.SalesOrderHeader.Include("SalesOrderDetail").Include("Address")
C#
// 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");
Visual Basic
Using context As New AdventureWorksEntities
    ' Create an object query with a path that returns orders and items for a contact.
    Dim contact As Contact = _
        context.Contact.Include("SalesOrderHeader.SalesOrderDetail") _
        .FirstOrDefault()
    Try
        ' Execute the query and display information for each item 
        ' in the orders that belong to the returned contact.
        Dim order As SalesOrderHeader
        For Each 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:")
            Dim item As SalesOrderDetail
            For Each item In order.SalesOrderDetail
                Console.WriteLine(String.Format("Product:{0}" _
                    + "Quantity: {1}", item.ProductID.ToString(), _
                    item.OrderQty.ToString()))
            Next
        Next
    Catch ex As EntitySqlException
        Console.WriteLine(ex.ToString())
    Catch ex As EntityCommandExecutionException
        Console.WriteLine(ex.ToString())
    End Try
End Using
C#
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
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