在XAML中将DateTime转换为LongDateString

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

namespace YourNamespace
{
    public class DateTimeToLongDateStringConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value is DateTime dateTime)
            {
                return dateTime.ToLongDateString();
            }

            return string.Empty;
        }

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

xmlns:local="clr-namespace:YourNamespace"

<TextBlock Text="{Binding YourDateTimeProperty, Converter={StaticResource DateTimeConverter}}" />

<Window.Resources>
    <local:DateTimeToLongDateStringConverter x:Key="DateTimeConverter" />
</Window.Resources>