public shared function nulltodate(byval obj as object) as date
          dim isvalid as boolean = false

          if obj is nothing then isvalid = false
          if isdbnull(obj) = false then isvalid = false
          if isdate(obj) = false then isvalid = false

          if isvalid = false then
              return new date(now.tostring("yyyy/mm/dd"))
          else
              return convert.todatetime(obj)
          end if
      end function