sql - vb.net Date equivalent to String.Empty -

in program, writing class read values in 1 database table, , copy them another. when reading string fields, have function called checks whether or not string value null, , if is, returns empty string, if not, returns string. (see code below)

i have datetime fields can contain nulls, , without similar function, runtime error when trying copy them.

is there equivalent of code below can use entering in blank date if value in database row null?

 public shared function dbtostring(o object) string      if o dbnull.value         return string.empty     else         return cstr(o)      end if end function 

datetime value type, therefore notion of 'blank' doesn't exist. use minvalue of datetime there might problems , intent might not clear. use nullable datetime instead:

public shared function dbtodate(o object) datetime?     if o dbnull.value         return nothing     else         return convert.todatetime(o)      end if end function