Entity Framework 4 Delete Object from entity collection
c#, entity-framework-4
Solution
The answer depends on the way you modeled your entities. If you are using common independent relation or foreign key relation you will have to use your current approach - I'm using it as well in my project.
If you defined identifying relation you will be able to call just `Clear` on collection as @Craig described. Identifying relation is special relation where primary key of dependent entity contains foreign key of parent entity.
The example shows `Order` entity and `OrderItem` entity with foreign key identifying relation between them. Primary key of `OrderItem` consists of unique `Id` and `OrderId` which is FK of `Order` table. With this configuration you don't need to iterate through `OrderItem`s and delete each item separately. Simply removing `OrderItem` from collection will be executed as delete in database and clearing collection will delete all related `OrderItem`s in database.
Problem
I have a "Request" Entity with an 1..* relationship to the "RequestProperty" Entity. So there's a collection of RequestProperty objects in "Request". When I update a "Request" I want to delete all items in the RequestProperty EntityCollection and add the new items from the incoming domain object. When I iterate over the `Request.Properties` collection and call a remove or a `DeleteObject` on the item, the enumeration fails because the collection has been modified. As of now I'm doing this: ``` while (true) { if (newRequest.Properties.Count > 0) context.RequestPropertySet.DeleteObject(newRequest.Properties.First()); else break; } ``` Since this is not really "cool" I thought there must be another way to empty a collection of a relationship. Thank you for your thoughts.