How to: Serialize and Deserialize Objects (Entity Framework)
Entity types generated by the Entity Data Model (EDM) generator tool (EdmGen.exe) and the Entity Data Model Wizard support binary serialization. When you serialize an object to a binary stream, all related objects currently loaded into the object context will also be serialized. For more information, see Serializing Objects (Entity Framework).
The example in this topic is based on the Adventure Works Sales Model. To run the code in this example, you must have already added the AdventureWorks Sales Model to your project and configured your project to use the Entity Framework. To do this, complete the procedures in How to: Manually Configure an Entity Framework Project and How to: Manually Define an Entity Data Model (Entity Framework). You must also add using statements (Imports in Visual Basic) for the following namespaces:
Example
In this example, a SerializeToBinaryStream method queries for the Contact object for the specified last name value, and returns a binary MemoryStream. The MemoryStream contains an object graph of the Contact object and its related SalesOrderHeader and SalesOrderDetail objects.
Public Shared Sub ReadFromBinaryStream()
Dim formatter As New BinaryFormatter
Using context As New AdventureWorksEntities()
Try
' Get the object graph for the selected customer
' as a binary stream.
Dim stream As MemoryStream = SerializeToBinaryStream("Adams")
' Read from the begining of the stream.
stream.Seek(0, SeekOrigin.Begin)
' Deserialize the customer graph from the binary stream
' and attach to an ObjectContext.
Dim contact As Contact = CType(formatter.Deserialize(stream), Contact)
context.Attach(contact)
' Display information for each item
' in the orders that belong to the contact.
For Each order As SalesOrderHeader 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:")
For Each item As SalesOrderDetail In order.SalesOrderDetail
Console.WriteLine(String.Format("Product:{0}" _
+ "Quantity: {1}", item.ProductID.ToString(), _
item.OrderQty.ToString()))
Next
Next
Catch ex As ApplicationException
Console.WriteLine(ex.ToString())
Catch ex As SerializationException
Console.WriteLine("The object graph could not be deserialized from " _
+ "the binary stream because of the following error:")
Console.WriteLine(ex.ToString())
End Try
End Using
End Sub
Private Shared Function SerializeToBinaryStream(ByVal lastName As String) As MemoryStream
Dim formatter As BinaryFormatter = New BinaryFormatter()
Dim stream As MemoryStream = New MemoryStream()
Using context As New AdventureWorksEntities
' Specify a timeout for queries in this context, in seconds.
context.CommandTimeout = 120
' Define a customer contact.
Dim customer As Contact
' Create a Contact query with a path that returns orders and items for a contact.
Dim query As ObjectQuery(Of Contact) = _
context.Contact '.Include("SalesOrderHeader.SalesOrderDetail")
Try
' Return the first contact with the specified last name
' along with its related orders and items.
customer = query.Where( _
"it.LastName = @lastname", _
New ObjectParameter("lastname", lastName)).First()
' Serialize the customer object graph.
formatter.Serialize(stream, customer)
Catch ex As EntitySqlException
Throw New ApplicationException("The object query failed", ex)
Catch ex As EntityCommandExecutionException
Throw New ApplicationException("The object query failed", ex)
Catch ex As SerializationException
Throw New ApplicationException("The object graph could not be serialized", ex)
End Try
' Return the streamed object graph.
Return stream
End Using
End Function
public static void ReadFromBinaryStream()
{
BinaryFormatter formatter = new BinaryFormatter();
using (AdventureWorksEntities context = new AdventureWorksEntities())
{
try
{
// Get the object graph for the selected customer
// as a binary stream.
MemoryStream stream = SerializeToBinaryStream(@"Adams");
// Read from the begining of the stream.
stream.Seek(0, SeekOrigin.Begin);
// Deserialize the customer graph from the binary stream
// and attach to an ObjectContext.
Contact contact = (Contact)formatter.Deserialize(stream);
context.Attach(contact);
// 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 (ApplicationException ex)
{
Console.WriteLine(ex.ToString());
}
catch (SerializationException ex)
{
Console.WriteLine("The object graph could not be deserialized from "
+ "the binary stream because of the following error:");
Console.WriteLine(ex.ToString());
}
}
}
private static MemoryStream SerializeToBinaryStream(string lastName)
{
BinaryFormatter formatter = new BinaryFormatter();
MemoryStream stream = new MemoryStream();
using (AdventureWorksEntities context = new AdventureWorksEntities())
{
// Specify a timeout for queries in this context, in seconds.
context.CommandTimeout = 120;
// Define a customer contact.
Contact customer;
// Create a Contact query with a path that returns
// orders and items for a contact.
ObjectQuery<Contact> query =
context.Contact.Include("SalesOrderHeader.SalesOrderDetail");
try
{
// Return the first contact with the specified last name
// along with its related orders and items.
customer = query.Where("it.LastName = @lastname",
new ObjectParameter("lastname", lastName)).First();
// Serialize the customer object graph.
formatter.Serialize(stream, customer);
}
catch (EntitySqlException ex)
{
throw new ApplicationException("The object query failed", ex);
}
catch (EntityCommandExecutionException ex)
{
throw new ApplicationException("The object query failed", ex);
}
catch (SerializationException ex)
{
throw new ApplicationException("The object graph could not be serialized", ex);
}
// Return the streamed object graph.
return stream;
}
}