Queryable::ThenBy<TSource, TKey> Method (IOrderedQueryable<TSource>^, Expression<Func<TSource, TKey>^>^)

Parameters

source

Type: System.Linq::IOrderedQueryable<TSource>^

An IOrderedQueryable<T> that contains elements to sort.

keySelector

Type: System.Linq.Expressions::Expression<Func<TSource, TKey>^>^

A function to extract a key from each element.

Return Value

An IOrderedQueryable<T> whose elements are sorted according to a key.

Type Parameters

TSource

The type of the elements of source.

TKey

The type of the key returned by the function represented by keySelector.

This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T, TResult> types. For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

The ThenBy<TSource, TKey>(IOrderedQueryable<TSource>^, Expression<Func<TSource, TKey>^>^) method generates a MethodCallExpression that represents calling ThenBy<TSource, TKey>(IOrderedQueryable<TSource>^, Expression<Func<TSource, TKey>^>^) itself as a constructed generic method. It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression^) method of the IQueryProvider represented by the Provider property of the source parameter. The result of calling CreateQuery<TElement>(Expression^) is cast to type IOrderedQueryable<T> and returned.

The query behavior that occurs as a result of executing an expression tree that represents calling ThenBy<TSource, TKey>(IOrderedQueryable<TSource>^, Expression<Func<TSource, TKey>^>^) depends on the implementation of the type of the source parameter. The expected behavior is that it performs a secondary sort of the elements of source based on the key obtained by invoking keySelector on each element of source. All previously established sort orders are preserved.