Can somebody give some guidelines about windows desktop applications suchas
when should WPF be used and when can win forms be used.
I know the difference so you don't have to explain that.
//Tony
It depends.
If you're writing a small app with few use-cases, that's not really "enterprisey", or maybe prototyping something out, you may find WinForms faster.
However, if you're beginning an app that has a long life-expectancy (several years) and a solid future in terms of new functionality etc, then WPF is almost certainly the way to go. If you do it properly and go with somethinglike MVVM you get better separation of logic from layout, and while XAML can be a steep learning curve, there are things like Pluralsight that will get you started in just a few hours, and the skills will be transferrable toWin8/Silverlight etc.
For anything other than a really very trivial app, I'd choose WPF every time.