EntityCollection(TEntity).Load Method (MergeOption)
Loads related objects into the collection, using the specified merge option.
Assembly: System.Data.Entity (in System.Data.Entity.dll)
abstract Load : mergeOption:MergeOption -> unit override Load : mergeOption:MergeOption -> unit
This method calls the ValidateLoad``1 method before loading the collection. See this method for a list of possible exceptions.
When objects in the collection are already loaded into the ObjectContext, the Load method enforces the MergeOption specified by the mergeOption parameter. For more information, see Managing the Object Context (Entity Framework).
To explicitly load related objects, you must call the Load method on the related end returned by the navigation property. For a one-to-many relationship, call the Load method on EntityCollection(TEntity). For a one-to-one relationship, call the Load on EntityReference(TEntity). This loads the related object data into the object context. You can enumerate through the collection of returned results using a foreach loop (For Each...Next in Visual Basic) and conditionally call the Load method on EntityReference(TEntity) and EntityCollection(TEntity) properties for each entity in the results.
When you call the Load method during a foreach (C#) or For Each (Visual Basic) enumeration, Object Services tries to open a new data reader. This operation will fail unless you have enabled multiple active results sets by specifying multipleactiveresultsets=true in the connection string. You can also load the result of the query into a List(T) collection. This closes the data reader and enables you to enumerate over the collection to load referenced objects.
This example 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 E*ntity Data Model (Entity Framework).
This example loads the related SalesOrderHeader objects for the Contact entity.