IsNullEntity Property

Returns whether the current instance is a null entity.

Syntax

Visual Basic
C#

'Declaration
 
Public ReadOnly Property IsNullEntity As Boolean

'Usage
 
Dim instance As EntityAspect
Dim value As Boolean
 
value = instance.IsNullEntity

public bool IsNullEntity {get;}

Remarks

The EntityManager will return a NullEntity instead of a null value when a requested entity is not found.

Example

// Sample showing IsNullEntity check.

    DomainModelEntityManager mgr = new DomainModelEntityManager();

    // Try to retrieve order #1 - FirstOrNullEntity will return null entity if not found.
    OrderSummary order = mgr.OrderSummaries.FirstOrNullEntity(o => o.Id == 1);
    if (order.IsNullEntity)
       Console.WriteLine("Order #1 not found");

    // Now try another order, using FirstOrDefault, which returns null if not found.
    OrderSummary order2 = mgr.OrderSummaries.FirstOrDefault(o => o.Id == 2);
    if (order2 == null) {
       Console.WriteLine("Order #2 is null");
    } else if (order2.IsNullEntity) {
       Console.WriteLine("Order #2 is a null entity");
    }

    // Note, you can't use .First (since the EF will throw an exception).
    OrderSummary order3 = mgr.OrderSummaries.First(o => o.Id == 3);

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

EntityAspect Class
EntityAspect Members