DiscordChatExporter/DiscordChatExporter.Gui/Converters/TimeSpanToDateTimeConverter.cs

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

namespace DiscordChatExporter.Gui.Converters;

[ValueConversion(typeof(TimeSpan?), typeof(DateTime?))]
public class TimeSpanToDateTimeConverter : IValueConverter
{
    public static TimeSpanToDateTimeConverter Instance { get; } = new();

    public object? Convert(object value, Type targetType, object parameter, CultureInfo culture) =>
        value is TimeSpan timeSpanValue ? DateTime.Today.Add(timeSpanValue) : default(DateTime?);

    public object? ConvertBack(
        object value,
        Type targetType,
        object parameter,
        CultureInfo culture
    ) => value is DateTime dateTimeValue ? dateTimeValue.TimeOfDay : default(TimeSpan?);
}