Powertips » Linq To Object http://scripting.chaindb.com Programmer tips Tue, 15 May 2012 23:56:52 +0000 en hourly 1 http://wordpress.org/?v=3.2.1 Linq Exception(NullReferenceException): Object reference not set to an instance of an object http://scripting.chaindb.com/2010/09/24/linq-exceptionnullreferenceexception-object-reference-not-set-to-an-instance-of-an-object/ http://scripting.chaindb.com/2010/09/24/linq-exceptionnullreferenceexception-object-reference-not-set-to-an-instance-of-an-object/#comments Fri, 24 Sep 2010 05:35:36 +0000 admin http://scripting.chaindb.com/?p=868 With NullReferenceException:

  1.  Dim obj As DemographicProperties = Me
  2.  
  3.         Dim m As IEnumerable(Of DemographicProperty) = From c In obj _
  4.                                                        Where (c.MapClass.MapClassID = MapClassID)  _
  5.                                                        Order By c.Name Ascending _
  6.                                                        Select c

If you are getting NullReferenceException, it means the MapClassID is null(nothing in vb.net)

Solve:

  1.  Dim obj As DemographicProperties = Me
  2.  
  3.         Dim m As IEnumerable(Of DemographicProperty) = From c In obj _
  4.                                                        Where ((Not c.MapClass Is Nothing) AndAlso (c.MapClass.MapClassID = MapClassID)) _
  5.                                                        Order By c.Name Ascending _
  6.                                                        Select c

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