EntityReference<TEntity>.Attach Method (TEntity)


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Creates a many-to-one or one-to-one relationship between two objects in the object context.

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

public void Attach(
	TEntity entity


Type: TEntity

The object being attached.

Exception Condition

When the entity is null.


When the entity cannot be related to the current related end. This can occur when the association in the conceptual schema does not support a relationship between the two types.

The Attach method is used to define a relationship between an object and a related object when both objects are already attached to an object context. Set the related object to the Value property if the related object is not already attached to the object context. When both objects are detached, you can also define the relationship by setting the related object to the Value property and then attaching the root object in the object graph. For more information, see Attaching and Detaching Objects.

The object associated with this EntityReference<TEntity> and all objects being attached to it must be in an Unchanged or Modified state.

An object in the Deleted state can only be attached when the ObjectStateManager is already tracking the relationship instance.

.NET Framework
Available since 3.5
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