[AccessD] A little Null Help Please

I have a situation where for some records there is no DOB
for an entry.

 

The details are messy but trying to be a good programmer I
am trying to code around it.

 

If DOB = Null Then

    txtAgeThisDay.Value = "No Dob"

    Else

    txtAgeThisDay = yearcalc(DOB, txTaCCIDENT_dATE) 'Calc
Age on Event Day

  End If

 

 

I have tested a record and know the DOB is null.  

 

txtAgeThisDay.Value = "No Dob" is not triggering.

 

Could some one please tell me why?

 

TIA

 

Joe Hecht

jmhecht at earthlink.net