Can't write empty values into numeric fields

[Plavozont]

Hello, sorry, maybe I am missing something obvious, but I can't write null values into numeric fields, all null values become zeroes in the end file. I create Object[] rowObjects = new Object[field.Count]; (which is not documented in a quick start some how)
Fill it like this
rowObjects[i] = ((field_value==DBNull.Value) ? null : field_value);
Or like this
rowObjects[i] = field_value;
Then
writer.AddRecord(rowObjects);
Then
writer.Write(fos);
In both cases I get zeroes, please help.

[UsernameNotFoundException]

This is expected behavior:
Null Values

The new DBF7 (dBASE) table type support nulls, as do most other tables, including DB (Paradox). Older DBF formats do not. (emphasis added)

The ability to store nulls was not introduced into dBASE. dBASE PLUS 7 has it, but these are not the same product.

Additional Context

... DBFs only have the concept of an "empty" value, which is usually a common value that fields normally contain. For example, 0 is the "empty" value for a DBF table, but 0 is often a legitimate value a numeric field can contain and is thus not suitable to be treated as a true NULL value.