Change SliderThumbStyle value from Slider definition - wpf

Question

I have this SliderThumbStyle:
<Style x:Key="SliderThumbStyle" TargetType="{x:Type Thumb}">
<Setter Property="OverridesDefaultStyle" Value="True"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Thumb}">
<Grid>
<Border Name="outerBorder"
Background="{DynamicResource ApplicationBorderBrush}"
BorderBrush="{DynamicResource ApplicationBorderBrush}"
Height="24"
Width="24"
Opacity="1"
BorderThickness="2"
CornerRadius="10"/>
<TextBlock x:Name="sliderValue"
FontSize="10"
Foreground="Silver"
Text="{Binding Value, RelativeSource={RelativeSource AncestorType=Slider}, StringFormat={}{0:N1}}"
VerticalAlignment="Center"
HorizontalAlignment="Center"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
In my application i am using this Slider Style twice but one of them not needed this N1 StringFormat but N0for only integer values.
Any idea how to choose this when i define my Slider in advanced ?
As mm8 suggestive i try this:
<Slider Tag="{Binding Value, RelativeSource={RelativeSource Self}, StringFormat=N1}" />
Style:
Text="{Binding Tag, RelativeSource={RelativeSource AncestorType=Slider}}"/>
But it seems that it now show the value in N1 format but 1.23456789
I also try this:
Tag="{Binding Value, RelativeSource={RelativeSource Self}, StringFormat={}{0:N1}}"

Answer 1

I am afraid you can't change the StringFormat without modifying the Style. What you could do is to bind to the Tag property of the Slider in your Style:
<TextBlock x:Name="sliderValue"
FontSize="10"
Foreground="Silver"
Text="{Binding Tag, RelativeSource={RelativeSource AncestorType=Slider}}"
VerticalAlignment="Center"
HorizontalAlignment="Center"/>
...and then handle the ValueChanged event of each individual Slider and set the Tag property to a formatted string:
private void slider_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
{
Slider slider = (Slider)sender;
slider.Tag = slider.Value.ToString("N1");
}
You may want to wrap this functionality an attached behaviour:
public class SliderFormatBehavior
{
public static string GetStringFormat(Slider treeViewItem)
{
return (string)treeViewItem.GetValue(StringFormatProperty);
}
public static void SetStringFormat(Slider slider, string value)
{
slider.SetValue(StringFormatProperty, value);
}
public static readonly DependencyProperty StringFormatProperty =
DependencyProperty.RegisterAttached(
"StringFormat",
typeof(string),
typeof(SliderFormatBehavior),
new UIPropertyMetadata(null, OnStringFormatChanged));
static void OnStringFormatChanged(DependencyObject depObj, DependencyPropertyChangedEventArgs e)
{
Slider slider = depObj as Slider;
if (slider != null)
{
if (slider.IsLoaded)
{
SetTag(slider);
}
else
{
slider.Loaded += Slider_Loaded;
}
slider.ValueChanged += Slider_ValueChanged;
}
}
private static void Slider_Loaded(object sender, RoutedEventArgs e)
{
Slider slider = (Slider)sender;
SetTag(slider);
slider.Loaded -= Slider_Loaded;
}
private static void Slider_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
{
SetTag((Slider)sender);
}
private static void SetTag(Slider slider)
{
slider.Tag = slider.Value.ToString(GetStringFormat(slider));
}
}
Sample usage:
<Slider ... local:SliderFormatBehavior.StringFormat="N1" />