Apache Lucene.Net 2.4.0 Class Library API

Token.StartOffset Method 

Returns this Token's starting offset, the position of the first character corresponding to this token in the source text. Note that the difference between endOffset() and startOffset() may not be equal to termText.length(), as the term text may have been altered by a stemmer or some other filter.

public int StartOffset();

See Also

Token Class | Lucene.Net.Analysis Namespace