Are there any implementations, api or examples of OrientDB and C#. The reason I am looking at OrientDB is becuase it's the only one that I found that is a combination of Graph and Document.
Any suggestions on how I should try this.
My next choice is RavenDB, but I am not sure if it supports joins or linked documents?
Any thoughts...
OrientDB has an official binary driver for .NET look here http://orientdb.com/docs/3.0.x/
Example of usage OrientDB-NET.binary
Regarding your second question on RavenDB, it doesn't have "joins" like in the relational sense but you can always store references to other documents by storing it's document id field. Here is the join question in the FAQ. One of the suggestions they give is to denormalize (store more than just the Id of the related document) which can be a big trade-off to make.
I just developed a first version of a REST client for OrientDB. http://netorientdb.codeplex.com
I just recently came across this repository. I haven't looked at the code or used it yet, but it has .NET interfaces for:
Pipes
These utilities can be used to connect with multiple Graph Databases (those that allow BluePrints) including neo4j and OrientDB. For more information also look at TikerPop.
Currently OrientDB supports both a REST/JSON protocol and a native binary protocol. There are Python and Javascript wrappers for the REST protocol whyle there are C and PHP wrappers for the native protocol. I don't know if a C# wrapper is in the working however looking at the specifications ( http://code.google.com/p/orient/wiki/OrientDB_REST ) writing one for C# should be straightforward. I have met in person the architect of the project at a JUG meeting and I must say that OrientDB is a very promising project. Also Luca Garulli ( the architect ) is a very available person, so you may write him if you need more information.