<Label Text="{Binding Name, StringFormat='Good morning {0}'}"
               HorizontalTextAlignment="Center">
            <Label.Triggers>
                <DataTrigger TargetType="Label"
                              Binding="{Binding Name}"
                     Value="">
                  <Setter Property="IsVisible" Value="False" />
             </DataTrigger>
           </Label.Triggers>
</Label>