ParallelEnumerable.DefaultIfEmpty<TSource> Method (ParallelQuery<TSource>)
.NET Framework (current version)
Returns the elements of the specified parallel sequence or the type parameter's default value in a singleton collection if the sequence is empty.
Assembly: System.Core (in System.Core.dll)
public static ParallelQuery<TSource> DefaultIfEmpty<TSource>( this ParallelQuery<TSource> source )
Parameters
- source
-
Type:
System.Linq.ParallelQuery<TSource>
The sequence to return a default value for if it is empty.
Return Value
Type: System.Linq.ParallelQuery<TSource>A sequence that contains default(TSource) if source is empty; otherwise, source.
Type Parameters
- TSource
The type of the elements of source.
| Exception | Condition |
|---|---|
| ArgumentNullException | source is a null reference (Nothing in Visual Basic). |
| OperationCanceledException | The query was canceled with the token passed in through WithCancellation. |
| AggregateException | One or more exceptions occurred during the evaluation of the query. |
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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