Showing unknown number of objects in WPF

It is possible but you need a container like the solution above said. You can create a list box and set the Template like this:

<ListBox x:name="myListBox">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>			
<TextBlocktext="{Binding path=Name}">
<Image Source="{Binding path=icon}">
</TextBlock>
</StackPanel>
</DataTemplate>			
</ListBox.ItemTemplate>
</ListBox>

In the code behind you can set the myListBox.ItemsSource = myFriends

As said you need a container. How you have the object render can be on the containers item template or you can set the objects rendering tempalte elsewhere.

For example:

<datatemplate datatype="{x:Type">
  <stackpanel>
   <textblock text="{Binding" path="Name}/">
   <image source="{Binding" path="Icon}/">
  </image></textblock></stackpanel>
</datatemplate>

As long as this was pulled in from a resource dictionary or defined in that controls resources it will render the object. Another option is to built the "Friend" view as a user control. That way you can modify it using the designer. If you do that you would do something like this:

<datatemplate>
   <local:friendview xmlns:local="#unknown" />
</datatemplate>

Where FriendView is a usercontrol set up as you want.

Then just set up your container (as others have pointed out)

 <listbox itemsource="{Binding" path="MyFriends}/">
</listbox>

Make sure MyFriends is public (you have it as private)