I found some open source R-Tree implementations in C#, but none with documentation nor signs of being used by someone else than the developer.
The NetTopologySuite is a JTS port to C# and it contains a STRtree class which is a read-only R-Tree
I know of none, but I would point out that libraries like this tend to:
- Get written (normally with some bugs).
- Bugs get ironed out though use.
- All active bugs are fixed
- Optional
- 'Latent' bugs which could never happen due to previous semantics of the platform on which the library operates crop up if the platform changes in some way.
Thus lack of activity in terms of commits for the library should not indicate that the library is dead, it may indicate it is very stable and solid. If the library is either easy to understand or targeted at a relatively sophisticated audience (as R-Tree usage currently is) then you may find little online dialogue about it.
Lack of download activity is somewhat worrying. Though you are using a fairly niche library on a platform not previously known for heavy GIS/spatial query work (though the changes in SQL Server 2008 may change that).
If you cannot find a Java library of appropriate activity it is unlikely you will find a c# one. If you find such a java one a direct (as opposed to idiomatic) port is unlikely to encouter problems.
According to this thread there is an R-Tree implementation as part of Perst: http://www.mcobject.com/perst_eval
来源：https://stackoverflow.com/questions/2041834/is-there-any-documented-free-r-tree-implementation-for-net