Where can I find Windows Live Style comment box for Windows Phone 7?

I am looking for a nice comment box, instead of creating something with textbox and a button. Windows live photos has a nice comment box under each photo, it is one line with a small triangle on left bottom , which makes it look like dialog box from comic books. It also has send button on the right inside the 开发者_JAVA百科box so no additional buttons. How can I do something like this ?

It is not that easy to find ready-to-go templates for input controls, so why not create your own? You can start by reading this MSDN article. All you need is learn the basics of templating and then you'll be able to reproduce the style you want.