Lucene.Net 1.9.1 Class Library

TermVectorsWriter.OpenField Method 

Start processing a field. This can be followed by a number of calls to addTerm, and a final call to closeField to indicate the end of processing of this field. If a field was previously open, it is closed automatically.

public void OpenField(
   string field
);

See Also

TermVectorsWriter Class | Lucene.Net.Index Namespace