db4o is an object database for Java and all .NET environments. Its features include ACID transactions, automatic class schema recognition, query-by-example, a S.O.D.A. object querying API, native queries, LINQ support on .NET, callback methods, memory files, cascade-on-delete, multi-threaded access, and Java Webstart and servlet support.
Silverlight Files Uploader is a Web application component for uploading multiple files to a Web server from a Web browser. It is provided in three variants: a control for ASP.NET, a control for Silverlight, and a Silverlight Module. Its main features are multiple file selection at once, selection of all files in a folder by using a hot-key, rich progress and status information during the upload process, file filters by extension in the "Choose Files" dialog, a limit to the maximum allowed size of files, the possibility to cancel an upload at any time, and compatibility with SSL (HTTPS) and any kind of authentication.
DotNetZip is a zip library for .NET and Silverlight. Using this library, you can build .NET or Silverlight applications that create, view, update, or unpack ZIP archives. DotNetZip also includes a ZLIB library and a BZip2 library. It is all managed code. Compact Framework versions of the libraries are included as well. The ZIP library supports WinZip AES encryption, regular PKZip encryption, Zip64, Unicode filenames, and many other ZIP features.