Assembly: System.Data.Entity (in System.Data.Entity.dll)
There are various ways to get an invalid entity. The most common scenario is when an Entity SQL query uses the TREAT operator to interpret an instance of a polymorphic type as a particular type, and the instance in question does not match. (TREAT is similar to the C# as operator). In this case, the query returns an entity that is not valid, and the entity key of the resulting entity is set to .
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.