ListBox displays text vertically

[Anubala]

Hi,in my code i call Add() for 10 time(For loop).The listbox should display 10 different items .
But what it shows,it dispaying last item only and also vertically.Like

S
T
R
I
N
G
And each letter as one item.


My code:
public void Add(string menu)
{
DataContext = menu.ToString();
}

XAML code of Listbox:

<ListBox x:Name="menubox" ItemsSource='{Binding}' Margin="0,5,0,0" Height="244" Width="240" Background="Silver" BorderThickness="0" > </ListBox>