How to select listbox item into textbox in wpf

Question

I have listbox with items,

I want to select items into text box from listbox.

<ListBox Name="listbox" Margin="118,77,293,103">
<ListBoxItem Content="Abc"/>
           <ListBoxItem Content="Pqr"/>
           <ListBoxItem Content="Xyz"/>
           <ListBoxItem Content="Lmn"/>
           <ListBoxItem Content="Tuv"/>
       </ListBox>