.NET API for Document Indexing & Text Search

Class Library to Index Data & Search Text in all popular document formats from Microsoft Word, Excel, PowerPoint, OneNote, Outlook as well as PDF, e-books, archives & more.

C# Document Search Engine

Create index in memory or on the local disk.
Merge several indexes.
Improve search performance by optimizing index.
Index password-protected files.
Index with stop words.
Support for indexing additional fields.
Supports blended characters.
Support for characters indexed as a whole word.
Support for character replacement during indexing.
Support for custom text extractors.
Option for compact and metadata index.
Save extracted text in index with different level of compression.
Document filtering during indexing.
Delete indexed paths from index.
Filter documents in search results.
Search for different object types, such as, text, numbers, dates, filenames etc.
Combining different types of search into one search query.
Alias substitution in search queries.
Perform spell check during search.
Perform keyboard layout correction during search.
Search queries in text or flexible object form.
Highlighting search results in the text of the entire document or in text segments.
Multiple simultaneous thread safe search.
Thread safe search during indexing, updating or merging operation.
Search over several indexes simultaneously.

New Features & Enhancements in Version 20.11

Get synonyms for a word as well as get synonym groups associated with a word.
Get homophones for a word and as well as get homophone groups to which a word belongs to.

Please visit GroupDocs.Search for .NET 20.11 Release Notes for the detailed notes.

Content Indexing

Metadata Indexing

Word Processing: DOC, DOT, DOCX, DOCM, DOTX, DOTM, TXT, ODT, OTT, RTF
Spreadsheets: XLS, XLT, XLSX, XLSM, XLSB, XLTX, XLTM, XLA, XLAM, ODS, OTS, CSV, TSV, XML
Presentations: PPT, PPS, POT, PPTX, PPTM, POTX, POTM, PPSX, PPSM, ODP
Emails: PST, OST, EML, EMLX, MSG
Notes: ONE
Archives: ZIP
Audio: MP3, WAV
Portable: PDF
Markup: HTML, XHTML, MHTML, MD, XML
eBook: CHM, EPUB, FB2
Image: BMP, GIF, JP2, PNG, WEBP, TIFF, JPG, PSD, DJVU, DICOM
Metafiles: EMF, WMF
Project Management: MPP
Torrent: TORRENT
Visio Diagram: VSD, VSS
Medical Imagery: DCM
Video: AVI, MOV, QT, FLV, ASF

Search Types

Simple word
Boolean
Regular expression
Faceted
Case sensitive
Flexible fuzzy
Synonym
Homophone
Wildcard
Phrase
Data range
Numeric range
Search by chunks
Object type search

Platform Independence

GroupDocs.Search for .NET does not require any external software or third party tool to be installed. GroupDocs.Search for .NET supports any 32-bit or 64-bit operating system where .NET or Mono framework is installed. The other details are as follows:

Microsoft Windows: Microsoft Windows Desktop (x86, x64) (XP & up), Microsoft Windows Server (x86, x64) (2000 & up), Windows Azure
macOS: Mac OS X
Linux: Linux (Ubuntu, OpenSUSE, CentOS and others)
Development Environments: Microsoft Visual Studio (2010 & up), Xamarin.Android, Xamarin.IOS, Xamarin.Mac, MonoDevelop 2.4 and later.
Supported Frameworks: GroupDocs.Search for .NET supports .NET and Mono frameworks.

Perform Regular Expression Search

string indexFolder = @"c:\MyIndex\";
string documentsFolder = @"c:\MyDocuments\";

// creating an index in the specified folder
Index index = new Index(indexFolder);

// indexing documents from the specified folder
index.Add(documentsFolder);

// search for the phrase in text form
// the first caret character at the beginning indicates that this is a regular expression search query
string query1 = "^^(.)\\1{1,}";
// search for two or more identical characters at the beginning of a word
SearchResult result1 = index.Search(query1); 

// search for the phrase in object form
// search for two or more identical characters at the beginning of a word
SearchQuery query2 = SearchQuery.CreateRegexQuery("^(.)\\1{1,}");
SearchResult result2 = index.Search(query2);

Spell Check with Smart Search

string indexFolder = @"c:\MyIndex\";
string documentsFolder = @"c:\MyDocuments\";

// creating an index in the specified folder
Index index = new Index(indexFolder);

// indexing documents from the specified folder
index.Add(documentsFolder);

// creating a search options instance
SearchOptions options = new SearchOptions();
// enabling the spelling correction
options.SpellingCorrector.Enabled = true;
// setting the maximum number of mistakes
options.SpellingCorrector.MaxMistakeCount = 1;
// enabling the option for only the best results of the spelling correction
options.SpellingCorrector.OnlyBestResults = true;

// search for the word "Rleativity" containing a spelling error
// the word "Relativity" will be found that differs from the search query in two transposed letters
SearchResult result = index.Search("Rleativity", options);