Considering how you are using WCF, you may want to look at WPF which is a more modern technology compared to WinForms.
Sacha Barber (a very popular author here) has a chat application article that was written using WCF/WPF, and Sacha is usually brilliant at maintaining best practices in his code and design. Take a look at it here:
WCF / WPF Chat Application[
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