Table<TEntity>.Attach Method (TEntity, TEntity)


Attaches an entity to the DataContext in either a modified or unmodified state by specifying both the entity and its original state.

Namespace:   System.Data.Linq
Assembly:  System.Data.Linq (in System.Data.Linq.dll)

public void Attach(
	TEntity entity,
	TEntity original


Type: TEntity

The entity to be attached.

Type: TEntity

An instance of the same entity type with data members that contain the original values.

In the following example, the Customer object is already correctly configured. You can call Attach without having to replay the updates.

When a new entity is attached, deferred loaders for any child collections (for example, EntitySet collections of entities from associated tables) are initialized. When SubmitChanges is called, members of the child collections are put into an Unmodified state. To update members of a child collection, you must explicitly call Attach and specify that entity.

using (Northwnd db2 = new Northwnd(@"c:\northwnd.mdf"))
    Customer Cust_File = new Customer();
    string xmlFile = "";

    // Get the original object from the deserializer.
    Customer c = SerializeHelper.Deserialize<Customer>
        (xmlFile, Cust_File);

    // Set all the desired properties to the entity to be attached.
    Customer c_updated = new Customer() { CustomerID = c.CustomerID,
        Phone = "425-123-4567", CompanyName = "Microsoft" };
    db2.Customers.Attach(c_updated, c);

    // Perform last minute updates, which will still take effect. 
    c_updated.Phone = "425-765-4321";

    // SubmitChanges()sets the phoneNumber and CompanyName of
    // customer with customerID=Cust. to "425-765-4321" and
    // "Microsoft" respectively.

.NET Framework
Available since 3.5
Windows Phone Silverlight
Available since 7.1
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