SingleOrNullEntity<TSource>(IEntityScalarQuery<TSource>) Method

Returns the only element of a sequence, or the appropriate NullEntity if the sequence is empty; this method throws an exception if there is more than one element in the sequence.

Syntax

Visual Basic
C#

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Function SingleOrNullEntity(Of TSource)( _
   ByVal source As IEntityScalarQuery(Of TSource) _
) As Task(Of TSource)

'Usage
 
Dim source As IEntityScalarQuery(Of TSource)
Dim value As Task(Of TSource)
 
value = EntityScalarAsyncExtensions.SingleOrNullEntity(Of TSource)(source)

[Extension()]
public static Task<TSource> SingleOrNullEntity<TSource>( 
   IEntityScalarQuery<TSource> source
)

Parameters

source

Type Parameters

TSource

Example

public async void AsyncSingleOrNullEntity() {
  Employee emp = await _entityManager.Employees.Where(e => e.Id == 1).AsScalarAsync().SingleOrNullEntity();
}

Requirements

Target Platforms: 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

Reference

EntityScalarAsyncExtensions Class
EntityScalarAsyncExtensions Members
Overload List