ParallelEnumerable.SingleOrDefault(Of TSource) Method (ParallelQuery(Of TSource), Func(Of TSource, Boolean))
.NET Framework (current version)
Returns the only element of a parallel sequence that satisfies a specified condition or a default value if no such element exists; this method throws an exception if more than one element satisfies the condition.
Assembly: System.Core (in System.Core.dll)
<ExtensionAttribute> Public Shared Function SingleOrDefault(Of TSource) ( source As ParallelQuery(Of TSource), predicate As Func(Of TSource, Boolean) ) As TSource
Parameters
- source
-
Type:
System.Linq.ParallelQuery(Of TSource)
The sequence to return the single element of.
- predicate
-
Type:
System.Func(Of TSource, Boolean)
A function to test an element for a condition.
Return Value
Type: TSourceThe single element of the input sequence that satisfies the condition, or default() if no such element is found.
Type Parameters
- TSource
The type of the elements of source.
| 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 | source is empty or multiple elements are returned. |
Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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