ObjectContext Constructor (String)


The .NET API Reference documentation has a new home. Visit the .NET API Browser on docs.microsoft.com to see the new experience.

Initializes a new instance of the ObjectContext class with the given connection string and default entity container name.

Namespace:   System.Data.Objects
Assembly:  System.Data.Entity (in System.Data.Entity.dll)

public ObjectContext(
	string connectionString


Type: System.String

The connection string, which also provides access to the metadata information.

Exception Condition

The connectionString is null.


The connectionString is invalid.


The metadata workspace is not valid.

The connectionString is a string that contains information that is required to access a conceptual model and to connect to a data source. The EntityConnectionStringBuilder class can be used to correctly format the string.

The generate a named connection string that is stored in the application's configuration file. This named connection string can be supplied instead of the connectionString parameter when instantiating the ObjectContext class.

The example in this topic is based on the AdventureWorks Sales Model. The example shows how to construct an ObjectContext.

// Create the ObjectContext.
ObjectContext context =
    new ObjectContext("name=AdventureWorksEntities");

// Set the DefaultContainerName for the ObjectContext.
// When DefaultContainerName is set, the Entity Framework only
// searches for the type in the specified container. 
// Note that if a type is defined only once in the metadata workspace
// you do not have to set the DefaultContainerName.
context.DefaultContainerName = "AdventureWorksEntities";

ObjectSet<Product> query = context.CreateObjectSet<Product>();

// Iterate through the collection of Products.
foreach (Product result in query)
    Console.WriteLine("Product Name: {0}", result.Name);

.NET Framework
Available since 3.5
Return to top