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

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>