如何在ListView控件中为默认情况下检查的第一个WPF RadioButton设置XAML？

I have a WPF ListView control containing a number of RadioButton controls using data binding. I'd like the first RadioButton in the group to be checked by default, preferably set in the XAML rather than programmatically, but haven't managed to achieve this.I have a WPF ListView control containing a numb