Queryable.ElementAt<TSource> Method
Returns the element at a specified index in a sequence.
Assembly: System.Core (in System.Core.dll)
public static TSource ElementAt<TSource>( this IQueryable<TSource> source, int index )
Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- Type: System.Linq.IQueryable<TSource>
An IQueryable<T> to return an element from.
- index
- Type: System.Int32
The zero-based index of the element to retrieve.
Return Value
Type: TSourceThe element at the specified position in source.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable<TSource>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).| Exception | Condition |
|---|---|
| ArgumentNullException | source is null. |
| ArgumentOutOfRangeException | index is less than zero. |
The ElementAt<TSource>(IQueryable<TSource>, Int32) method generates a MethodCallExpression that represents calling ElementAt<TSource>(IQueryable<TSource>, Int32) itself as a constructed generic method. It then passes the MethodCallExpression to the Execute<TResult>(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 ElementAt<TSource>(IQueryable<TSource>, Int32) depends on the implementation of the type of the source parameter. The expected behavior is that it returns the item at position index in source.
The following code example demonstrates how to use ElementAt<TSource>(IQueryable<TSource>, Int32) to return an element at a specific position in a sequence.
string[] names = { "Hartono, Tommy", "Adams, Terry", "Andersen, Henriette Thaulow", "Hedlund, Magnus", "Ito, Shu" }; Random random = new Random(DateTime.Now.Millisecond); string name = names.AsQueryable().ElementAt(random.Next(0, names.Length)); Console.WriteLine("The name chosen at random is '{0}'.", name); /* This code produces the following sample output. Yours may be different due to the use of Random. The name chosen at random is 'Ito, Shu'. */
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
