Also I am seeing that last version of https://code.google.com/p/qt4dotnet/ is 4 years old?
There are a number of Gui toolkits to choose from, see e.g. http://www.mono-project.com/docs/gui/gui-toolkits/
All should work with microsofts framework just like they do with mono.
Also I am seeing that last version of https://code.google.com/p/qt4dotnet/ is 4 years old?