C# bindings for Xapian

The C# bindings for Xapian are packaged in the Xapian namespace and largely follow the C++ API, with the following differences and additions. C# strings and other types, etc., are converted automatically in the bindings, so generally it should just work as expected.

The examples subdirectory contains examples showing how to use the C# bindings based on the simple examples from xapian-examples: SimpleIndex.cs, SimpleSearch.cs.

Method Naming Conventions

Methods are renamed to use the "CamelCase" capitalisation convention which C# normally uses. So in C# you use GetDescription instead of get_description.

Exceptions

Exceptions are thrown as SWIG exceptions instead of Xapian exceptions. This isn't done well at the moment; in future we will throw wrapped Xapian exceptions. For now, it's probably easier to catch all exceptions and try to take appropriate action based on their associated string.

Iterators

The C#-wrapped iterators work much like their C++ counterparts, with operators "++", "--", "==", and "!=" overloaded. E.g.:

   Xapian.MSetIterator m = mset.begin();
   while (m != mset.end()) {
     // do something
     ++m;
   }

Iterator dereferencing

C++ iterators are often dereferenced to get information, eg (*it). In C# these are all mapped to named methods, as follows:

Other methods, such as MSetIterator.GetDocument(), are available unchanged.

MSet

MSet objects have some additional methods to simplify access (these work using the C++ array dereferencing):

Database Factory Functions

• Xapian::Auto::open_stub() is wrapped as Xapian.Auto.OpenStub()
• Xapian::Quartz::open() is wrapped as Xapian.Quartz.Open()
• Xapian::InMemory::open() is wrapped as Xapian.InMemory.Open()
• Xapian::Remote::open() is wrapped as Xapian.Remote.Open() (only the TCP version is currently wrapped, the "program" version isn't).

Constants

The Xapian::DB_* constants are currently wrapped in a Xapian class within the Xapian namespace, so have a double Xapian prefix! So Xapian::DB_CREATE_OR_OPEN is available as Xapian.Xapian.DB_CREATE_OR_OPEN. The Query::OP_* constants are wrapped a little oddly too: Query::OP_OR is wrapped as Xapian.Query.op.OP_OR. The naming here needs sorting out...

Query

In C++ there's a Xapian::Query constructor which takes a query operator and start/end iterators specifying a number of terms or queries, plus an optional parameter. This isn't currently wrapped in C#.