Decimal Value and other type value converter

public class DecimaValuelConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            return string.Format("{0:0.00}", value == null ? 0 : value);
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            return value;
        }
    }
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public class DefaultDateToEmptyConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            return value == null ? String.Empty : value.ToString() == "01/01/0001 12:00:00 AM" ? String.Empty : value;          
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            return value;
        }
    }
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public class VisibilityConverter : IValueConverter
    {
        public object Convert(
        object value,
        Type targetType,
        object parameter,
        CultureInfo culture)
        {
            bool visibility = (bool)value;
            return visibility ? Visibility.Visible : Visibility.Collapsed;
        }

        public object ConvertBack(
            object value,
            Type targetType,
            object parameter,
            CultureInfo culture)
        {
            Visibility visibility = (Visibility)value;
            return (visibility == Visibility.Visible);
        }
    }
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