<ExtensionAttribute()>
Public Overloads Shared Function FirstOrNullEntity(Of TEntity As Class)( _
   ByVal source1 As IEntityQuery(Of TEntity) _
) As TEntity

Dim source1 As IEntityQuery(Of TEntity)
Dim value As TEntity
 
value = EntityQueryExtensions.FirstOrNullEntity(Of TEntity)(source1)

[ExtensionAttribute()]
public static TEntity FirstOrNullEntity<TEntity>( 
   IEntityQuery<TEntity> source1
)
where TEntity: class

[ExtensionAttribute()]
public:
static TEntity^ FirstOrNullEntitygeneric<typename TEntity>
( 
   IEntityQuery<TEntity^>^ source1
) 
where TEntity: ref class

var mgr1 = new DomainModelEntityManager();
Customer cust = mgr1.Customers.Where(c => c.Country == "UK").FirstOrNullEntity();