Converters.cs

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Data;

namespace AppRTCDemo
{
    public class InvertVisibilityConverter : IValueConverter
    {

        public Object Convert(Object value, Type targetType, Object parameter, CultureInfo culture)
        {
            if (targetType == typeof(Visibility))
            {
                Visibility vis = (Visibility)value;
                return vis == Visibility.Collapsed ? Visibility.Visible : Visibility.Collapsed;
            }
            throw new InvalidOperationException("Converter can only convert to value of type Visibility.");
        }

        public Object ConvertBack(Object value, Type targetType, Object parameter, CultureInfo culture)
        {
            throw new Exception("Invalid call - one way only");
        }
    }
}