Question

I just want to create a slider in my C# WPF project and write the value of the slider into a label. I know this is probably really easy to do but I can’t manage to get it working. So here is my slider in my XAML code:

<Slider Height="21" Minimum="-255" Maximum="255" x:Name="sld_brightness" />
<Label x:Name="lb_brightness_nb" />

Now, I try to change the value of the label according to the slider value in my C# code:

public void sld_brightness_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
{
    lb_brightness_nb.Content = (int)sld_brightness.Value;
}

This code does compile but doesn’t do anything. It is not working. What’s wrong?

Answer 1

You could bind it directly; there’s no need to create an event handler for this.

<Slider Height="21" Minimum="-255" Maximum="255" x:Name="sld_brightness" />
<Label x:Name="lb_brightness_nb"
    Content="{Binding ElementName=sld_brightness,Path=Value,Converter={StaticResource DoubleToStringConverter}}" />

---

If you want to use the event handler, then it looks like you’re missing the wireup:

<Slider Height="21" Minimum="-255" Maximum="255" x:Name="sld_brightness"
    ValueChanged="sld_brightness_ValueChanged" />

Edit

To show only the integer, use an IValueConverter. Add it to the resources section using <local:DoubleToStringConverter x:Key="DoubleToStringConverter" />.

public class DoubleToStringConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return Math.Round((double)value);
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}