Queryable::SelectMany<TSource, TResult> Method (IQueryable<TSource>^, Expression<Func<TSource, IEnumerable<TResult>^>^>^)


Projects each element of a sequence to an IEnumerable<T> and combines the resulting sequences into one sequence.

Namespace:   System.Linq
Assembly:  System.Core (in System.Core.dll)

generic<typename TSource, typename TResult>
static IQueryable<TResult>^ SelectMany(
	IQueryable<TSource>^ source,
	Expression<Func<TSource, IEnumerable<TResult>^>^>^ selector


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

A sequence of values to project.

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

A projection function to apply to each element.

Return Value

Type: System.Linq::IQueryable<TResult>^

An IQueryable<T> whose elements are the result of invoking a one-to-many projection function on each element of the input sequence.

Type Parameters


The type of the elements of source.


The type of the elements of the sequence returned by the function represented by selector.

Exception Condition

source or selector is null.

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 SelectMany<TSource, TResult>(IQueryable<TSource>^, Expression<Func<TSource, IEnumerable<TResult>^>^>^) method generates a MethodCallExpression that represents calling SelectMany<TSource, TResult>(IQueryable<TSource>^, Expression<Func<TSource, IEnumerable<TResult>^>^>^) itself as a constructed generic method. It then passes the MethodCallExpression to the CreateQuery(Expression^) method of the IQueryProvider represented by the Provider property of the source parameter.

The query behavior that occurs as a result of executing an expression tree that represents calling SelectMany<TSource, TResult>(IQueryable<TSource>^, Expression<Func<TSource, IEnumerable<TResult>^>^>^) depends on the implementation of the type of the source parameter. The expected behavior is that it invokes selector on each element of source to project it into an enumerable form. It then concatenates the enumerable results into a single, one-dimensional sequence.

The following code example demonstrates how to use SelectMany<TSource, TResult>(IQueryable<TSource>^, Expression<Func<TSource, IEnumerable<TResult>^>^>^) to perform a one-to-many projection over an array.

No code example is currently available or this language may not be supported.

Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.1
Windows Phone
Available since 8.1
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