在WP7上格式化XAML中的日期

Question

有没有办法使用XAML为Windows Phone 7格式化日期？

如果尝试使用:

<TextBlock Text="{Binding Date, StringFormat={}{0:MM/dd/yyyy}}" />

但我得到错误:

在'Binding'类型中找不到属性'StringFormat'

Answer 1

在SL4内这是可能的......

<TextBlock Text="{Binding Date, StringFormat='MM/dd/yyyy'}}"/>

...在SL3中你需要使用IValueConverter.

public class DateTimeToStringConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return String.Format("{0:MM/dd/yyyy}", (DateTime)value);
    }

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

如果你想要一个更强大的方法,你可以使用ConverterParameter.

    public class DateTimeToStringConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
                if (parameter == null)
                    return ((DateTime)value).ToString(culture);
                else
                    return ((DateTime)value).ToString(parameter as string, culture);
        }

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

然后在您的XAML中,您首先将转换器定义为资源...

<namespace:DateTimeToStringConverter x:Key="MyDateTimeToStringConverter"/>

..然后引用它以及用于格式化DateTime值的可接受参数...

<TextBlock Text="{Binding Date, 
         Converter={StaticResource MyDateTimeToStringConverter}, 
         ConverterParameter=\{0:M\}}"/>