如何在Blend中动态更改UserControl的外观？

I'm new to Blend and XAML, and I've got a UserControl containing just a white rounded off rectangle and a label with black text. However, when the UserControl is clicked, I want the rectangle to change to Blue and the label text to White, to emulate a sort of selected look. What is the best way to do this? I'm not familiar with XAML so I was hoping there'd be a solution where I can just set two templates for it in Blend, and then in that UserControl code window, have a click event handler where I just tell it to switch over to the other template. ThanksI'm new to Blend and XAML, and I've got a UserC