If you have a value between 1 and 6 and you know what the style should be for each, you should just set a style that has datatriggers for each value (1-6) and set whatever values inside each trigger
<Window x:Class="WpfApplication8.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Window.Style>
<Style TargetType="{x:Type Window}">
<Setter Property="Background" Value="Pink" />
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=textbox, Path=Text}" Value="1">
<Setter Property="Background" Value="Green"/>
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=textbox, Path=Text}" Value="2">
<Setter Property="Background" Value="Red"/>
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=textbox, Path=Text}" Value="3">
<Setter Property="Background" Value="Blue"/>
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=textbox, Path=Text}" Value="4">
<Setter Property="Background" Value="Orange"/>
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=textbox, Path=Text}" Value="5">
<Setter Property="Background" Value="Indigo"/>
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=textbox, Path=Text}" Value="6">
<Setter Property="Background" Value="Violet"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Style>
<Grid Background="Transparent">
<TextBox x:Name="textbox" Width="200" Height="30" />
</Grid>