ParallelEnumerable.Single<TSource> Method (ParallelQuery<TSource>, Func<TSource, Boolean>)
.NET Framework 4
Returns the only element of a parallel sequence that satisfies a specified condition, and throws an exception if more than one such element exists.
Assembly: System.Core (in System.Core.dll)
public static TSource Single<TSource>( this ParallelQuery<TSource> source, Func<TSource, bool> predicate )
Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- Type: System.Linq.ParallelQuery<TSource>
The sequence to return the single element of.
- predicate
- Type: System.Func<TSource, Boolean>
A function to test an element for a condition.
Return Value
Type: TSourceThe single element of the input sequence that satisfies a condition.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type ParallelQuery<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 |
|---|---|
| OperationCanceledException | The query was canceled with the token passed in through WithCancellation. |
| ArgumentNullException | source or predicate is a null reference (Nothing in Visual Basic). |
| AggregateException | One or more exceptions occurred during the evaluation of the query. |
| InvalidOperationException | No element satisfies the condition in predicate. -or- More than one element satisfies the condition in predicate. |
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
