Drag and drop GUI Generator based on XML

[longitude]

I have my own XML to UI definition and my own XML to UI render engine.For example:\[code\]<YearOfBirth name='Year Of Birth' type="dropdown"><Option value="http://stackoverflow.com/questions/10455365/2000"/><Option value="http://stackoverflow.com/questions/10455365/2001"/></YearOfBirth>\[/code\]What you will see in UI will be a dropdown box with "2000" and "2001" option in it.Now, I want to create a drag and drop tool so that developers can just design the UI by dragging and dropping different components instead of writing/editing the xml. Once the drag and drop is done, the xml is automatically generated.Is there any commercial tools or frameworks I can leverage to achieve this?Thanks a lot.