3

I'm somehow doing it wrong, but I can't figure it out:

I have a model like this:

public class Person : IDataErrorInfo {
  public DateTime Birthdate {
    get { return _birthdate; }
    set {
      if (!Valid(value))
        AddError("Birthdate", "Birthdate not valid");

      _birthdate = value;
    }
  }
}

A ValueConverter like this:

public class DateToStringConverter : IValueConverter {
  public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) {
    return date.Date.ToShortDateString();
  }

  public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) {
    DateTime result;

    if (DateTime.TryParse(text, out result))
    {
      return result;
    }

    return DependencyProperty.UnsetValue;
  }
}

And a View like this:

<TextBox Text="{Binding Person.Birthdate,
                        Mode=TwoWay,
                        Converter={StaticResource DateToStringConverter},
                        ValidatesOnDataErrors=True}" />

If someone modifies an valid date like "1.1.1950" into an invalid date like "1.1.abc", the value does not get through to the Person and doesn't invalidate it. But a red border around the birthdate-textbox is shown. How can I keep the invalid text (to be modified by the user) and register an error for IDataErrorInfo?

tobiaswalter
  • 31
  • 1
  • Should there be an else statement in the setter? if(!Valid(value) ... else _birthday = value; – SwDevMan81 Mar 18 '10 at 19:02
  • No, why? Calling a set from outside, I think it should really set the value (or throw an ArgumentException). If the value is invalid, the object is in an invalid state then. Neglecting to set it would leave the object in a valid state - but with the old value. I think that's wrong. – tobiaswalter Mar 19 '10 at 06:24

0 Answers0