How to search a Lucene.Net index in C#

By Benjamin Perkins · ·

I used this code to perform a search of a Lucene.Net index.

Lucene.Net.Store..Directory directory =
     Lucene.Net.Store.FSDirectory
               .Open(new DirectoryInfo(textBoxSearchIndex.Text));
Lucene.Net.Analysis.Analyzer analyzer =
     new Lucene.Net.Analysis.Standard
                   .StandardAnalyzer(LuceneUtil.Version.LUCENE_29);
Lucene.Net.Search.Searcher searcher =
     new Lucene.Net.Search
               .IndexSearcher(LuceneIndex.IndexReader
                                         .Open(directory, true));
Lucene.Net.Search.Query query =
     new Lucene.Net.QueryParsers
               .QueryParser(LuceneUtil.Version.LUCENE_29,
                            "contents", analyzer)
                            .Parse(textBoxSearch.Text);
Lucene.Net.Search.Hits hits = searcher.Search(query);

Put these lines of code within a for loop.

LuceneDocument.Document doc = hits.Doc(i);
string result = "Contents: " + doc.Get("contents");

Reading in the source code I found that the Search method which returns a Hits class will be depreciated in 3.0. Even though the above worked, I decided to implement a solution that will work with future versions of Lucene.Net. Below is what I change my code to look like.

LuceneStore.Directory directory =
    LuceneStore.FSDirectory
               .Open(new DirectoryInfo(textBoxSearchIndex.Text));
const int HITS_PER_PAGE = 20;
Analyzer analyzer =
    new StandardAnalyzer(LuceneUtil.Version.LUCENE_29);
LuceneSearch.Query query =
    new LuceneQueryParsers
        .QueryParser(LuceneUtil.Version.LUCENE_29,
                     "contents", analyzer)
                     .Parse(textBoxSearch.Text);
LuceneSearch.Searcher searcher =
    new LuceneSearch.IndexSearcher(LuceneIndex.IndexReader
                                  .Open(directory, true));
TopScoreDocCollector collector =
    TopScoreDocCollector.create(HITS_PER_PAGE, true);
searcher.Search(query, collector);
ScoreDoc[] hits = collector.TopDocs().scoreDocs;

Put these lines of code within a for loop.

int docId = hits[i].doc;
LuceneDocument.Document doc = searcher.Doc(docId);
string result = "Contents: " + doc.Get("contents");