Question

in the below code transmittalno.TransID always has value but doctranstocon.Transid sometimes has value and sometimes does not, so when doctranstocon.Transid has value I have no problem but when there is not any value, when compare in the where clause like :transmittalno.TransID == doctranstocon.Transid.
It returns error ” Object reference not set to an instance of an object.”

TranstoCons = from doctranstocon in _DocTranstoCons where 
              ( transmittalno.TransID == doctranstocon.Transid  ) 
              select doctranstocon.tblTranstoCon

I like TranstoCons returns null when there is not any value for ” doctranstocon.Transid “

How I can handle this error in the below linq query:

var query = from transmittalno in _Transmittals
            Select new TransmittaltoConPresentationModel 
            { 
              TransID = transmittalno.TransID, 
              Transmittal = transmittalno.TRANSMITTAL, 
              TranstoCons = from doctranstocon in _DocTranstoCons where 
                            ( transmittalno.TransID == doctranstocon.Transid  ) 
                            select doctranstocon.tblTranstoCon 
             };

Answer 1

You can use this:

where doctranstocon != null && doctranstocon.Transid.Equals(transmittalno.TransID)