re-using a linq variable - vb.net

Question

I am successfully using some linq to populate some variables but in order to make it more efficient I would like to avoid the current repetition when setting the variables nextMDTID, nextPatientID, nextCareID and nextMDTDate.
Can I create a variable to hold the data generated using the linq query and then re-use it to avoid the repetition?
Dim thisPTOrder = (From p In ThisMDTData Where p.MDTID = Request.QueryString("MDTID") Select p.PTOrder).FirstOrDefault
Dim nextPTOrder = thisPTOrder + 1
Dim d = ThisMDTData.Where(Function(p) p.PTOrder = nextPTOrder And p.PTOrder <= p.PTOrder)
Dim nextMDTID = (From p In ThisMDTData Where p.PTOrder = nextPTOrder And p.PTOrder <= p.MaxPTOrder Select p.MDTID).FirstOrDefault
Dim nextPatientID = (From p In ThisMDTData Where p.PTOrder = nextPTOrder And p.PTOrder <= p.MaxPTOrder Select p.PatientID).FirstOrDefault
Dim nextCareID = (From p In ThisMDTData Where p.PTOrder = nextPTOrder And p.PTOrder <= p.MaxPTOrder Select p.CareID).FirstOrDefault
Dim nextMDTDate = (From p In ThisMDTData Where p.PTOrder = nextPTOrder And p.PTOrder <= p.MaxPTOrder Select p.MDTDate).FirstOrDefault

Answer 1

Using a proper definition for d, you can simplify the results extraction:
Dim d = ThisMDTData.Where(Function(p) p.PTOrder = nextPTOrder And p.PTOrder <= p.MaxPTOrder).Select(Function(p) New With { p.MDTID, p.PatientID, p.CareID, p.MDTDate }).FirstOrDefault
Dim nextMDTID = d?.MDTID
Dim nextPatientID = d?.PatientID
Dim nextCareID = d?.CareID
Dim nextMDTDate = d?.MDTDate
Putting the Select/FirstOrDefault on the definition of d ensures that any database is only queried once for the minimally needed data. You could leave the Select off if the row size is small, or the row only has those four properties. You can use the obvious fluent query translation for d if desired.
NOTE: If you don't want some of the variables to be Nullable, use If:
Dim nextPatientID = If(d?.PatientID, CType(Nothing, Integer))