WPF and Winforms are different programming languages and you should try and use only one or the other.
You can call one type in another, but it should only be for legacy systems and really not for any new application.
Thanks for your comments.. you are right... I recently joined code project... I was not familiar with the site when i joined... Initially I posted this question in C# discussion section... I did not see or realize the WPF/Silverlight forum... Then I posted the question here i thought this was the right place for this question... thanks for your feed back...I'll make sure I don't cross post question in the future...