HC_APTBS/Converters/NullToVisibilityConverter.cs

using System;
using System.Globalization;
using System.Windows;
using System.Windows.Data;

namespace HC_APTBS.Converters
{
    /// <summary>
    /// Returns <see cref="Visibility.Visible"/> when the value is non-null,
    /// and <see cref="Visibility.Collapsed"/> when the value is null.
    /// </summary>
    public sealed class NullToVisibilityConverter : IValueConverter
    {
        public object Convert(object? value, Type targetType, object parameter, CultureInfo culture)
            => value is null ? Visibility.Collapsed : Visibility.Visible;

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
            => throw new NotSupportedException();
    }
}