NClass

NClass is a free tool to easily create UML class diagrams with full C# and Java language support. The user interface is designed to be simple and user-friendly for easy and fast development.

Properties, enums, delegates and other language specific elements are fully supported with strict syntactical and semantical verification.

The main goal is to provide a simple but powerful class designer that is very intuitive to use. Diagram styles help you to create professional looking diagrams, just like in Visual Studio or other commercial products. Furthermore, you can generate code from your models or you can also import classes from existing .NET assemblies.