<ExtensionAttribute()>
Public Overloads Shared Function FirstOrNullEntity(Of TEntity As Class)( _
   ByVal source1 As IQueryable(Of TEntity), _
   ByVal predicate As Expression(Of Func(Of TEntity,Boolean)) _
) As TEntity

Dim source1 As IQueryable(Of TEntity)
Dim predicate As Expression(Of Func(Of TEntity,Boolean))
Dim value As TEntity
 
value = EntityQueryExtensions.FirstOrNullEntity(Of TEntity)(source1, predicate)

[ExtensionAttribute()]
public static TEntity FirstOrNullEntity<TEntity>( 
   IQueryable<TEntity> source1,
   Expression<Func<TEntity,bool>> predicate
)
where TEntity: class

[ExtensionAttribute()]
public:
static TEntity^ FirstOrNullEntitygeneric<typename TEntity>
( 
   IQueryable<TEntity^>^ source1,
   Expression<Func<TEntity^,bool>^>^ predicate
) 
where TEntity: ref class

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