Languages/QtSharp
Qt# was an attempt to create a set of classes that bind the C# language to the Qt toolkit. The bindings appear abandoned based on the Qt# home page.
The Qyoto/Kimono project are SMOKE based bindings which use the mono C# compiler for use with Qt and KDE that are very similar to C++/Qt syntax but with the addition of the unique syntactic constructs of C#. Because .NET is a multi-language VM, a variety of languages should be able to access the bindings.
You can get the latest code via svn://anonsvn.kde.org/home/kde/trunk/KDE/kdebindings or use the KDE bindings module from the KDE 4.x releases.
Mono is an open source implementation of the .NET Development Framework.