Passing state of WPF ValidationRule to View Model in MVVM

Question

I am stuck in a seemingly common requirement. I have a WPF Prism (for MVVM) application. My model implements the IDataErrorInfo for validation. The

Answer 1

I encountered the same problem and solved it with a trick. See the converter below:

public class IntValidationConverter : IValueConverter
{
    static string[] AllValuse = new string[100000];
    static int index = 1;
    public static int StartOfErrorCodeIndex = -2000000000;
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value == null) return null;
        if (value.ToString() == "") return null;

        int iValue = (int)(value);

        if (iValue == int.MinValue) return null;

        if (iValue >= StartOfErrorCodeIndex) return value;
        if ((iValue < IntValidationConverter.StartOfErrorCodeIndex) && (iValue > int.MinValue)) return AllValuse[StartOfErrorCodeIndex - iValue];

        return null;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value == null) return int.MinValue;
        if (value.ToString() == "") return int.MinValue;

        int result;
        bool success = int.TryParse(value.ToString(), out result);
        if (success) return result;

        index++;
        AllValuse[index] = value.ToString();
        return StartOfErrorCodeIndex - index;
    }
}