如何在WPF中同步ListBox SelectedItem和焦点项?

I create buttons as ListBox items. Using keyboard shortcut, the selected item/button will be changed to the button where the first character is the same with the pressed key. The problem is the focused item (dashed rectangle) will not be synchronized with selected item. This problem doesn't exist if we use keyboard arrow. The shorted code is:I create buttons as ListBox items. Using keyboa