Format Date in Silverlight 4

In Silverlight 3, to format a date, you needed to write a Converter class that implemented the IValueConverter interface and you needed to implement the Convert and ConvertBack methods – something similar to the following:

public class DateConverter: IValueConverter
{
    public object Convert(object value, Type targetType,
        object parameter, System.Globalization.CultureInfo culture)
    {
        DateTime dt = (DateTime)value;
        return dt.ToShortDateString();
    }

    public object ConvertBack(object value, Type targetType,
        object parameter, System.Globalization.CultureInfo culture)
    {
        string str = value.ToString();
        DateTime dt = DateTime.MinValue;

        if (DateTime.TryParse(str, out dt))
        {
            return dt;
        }
        return value;
    }
}

You then needed to add a reference to your class and write the following markup to format the date

<TextBox Text="{Binding Path=SomeDate,
Converter={StaticResource DateConverter}}" />

Silverlight 4 introduces the StringFormat binding property that makes formatting absolutely simple. You can format a value using either a predefined format or a custom format and the best part is, you do not need to write a converter class.

So to format a date in “dd/MM/yyyy” format, all you need to do is write the following markup

<TextBox Text="{Binding Path=SomeDate, StringFormat='dd/MM/yyyy'}"/>

which will produce the output 18/05/2010. Simple is good!