ScrollViewer in StackPanel

Question

<StackPanel Name="mypanel">
   <ScrollViewer Height="{Binding ElementName=mypanel, Path=ActualHeight}">

I need, that Height = mypanel.ActualHeight-60. How to do it?

Answer 1

You need to write an IValueConverter that takes in the ActualHeight and returns a new value of that minus 60.

Something like:

[ValueConversion(typeof(double), typeof(double))]
public class HeightAdjustmentConverter: IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        double original = (double)value;
        return double - 60;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        double adjusted = (double)value;
        return adjusted + 60;
    }
}

Answer 2

<StackPanel Name="mypanel">
        <ContentControl Content="{Binding HeaderPart}" /> <= here must be Expander
        <ScrollViewer Height="{Binding ElementName=mypanel, Path=ActualHeight, Converter={StaticResource HeightConverter}}" >
            <StackPanel>
            </StackPanel>
        </ScrollViewer>

When There is no Expander, all are working. When Expander is, mypanel.ActualHeight in HeightAdjustmentConverter = 0

What happend?