How do i extract an item out of a session object? - xaml

Question

Still learning visual studio and it's elements :-)
My question is as follows...
How do i extract "for example" the [clientname] out of session object using a xaml resource designer?
The session it's self is "CurrentSession" realistically i would like this to be dynamic so that i could use my listview template on any listview. I have been following the courses Here and this has helped me immensely but i cannot seem to work out how to do this from a session object, any help would be greatly appreciated :-)
a part of my xaml designer for a listview....
<DataTemplate x:Key="templateListBoxItem">
<Grid Margin="5">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Border Grid.Column="0"
Grid.Row="0"
Grid.RowSpan="2"
Margin="0,0,10,0">
<Image Source="{DynamicResource IMS}"
Stretch="Fill"
Height="20"
Width="20"/>
</Border>
<ItemsControl ItemsSource="{Binding CurrentSession[clientName]}">
<TextBlock Text="{Binding clientName}"
Grid.Row="0"
Grid.Column="1"
FontWeight="Bold"/>
</ItemsControl>
</Grid>
</DataTemplate>