Question

I need to print in a textBlock repeat if a number is less than 80 and paint color red, and more or equal than 80 print successful with green color.

How can I do that in XAML?

Answer 1

Converters.

Sadly there are no inequality-triggers or the like, so using a converter should do.

<TextBlock>
    <TextBlock.Foreground>
        <Binding Path="TestDouble">
            <Binding.Converter>
                <vc:ThresholdConverter BelowValue="{x:Static Brushes.Red}"
                                       AboveValue="{x:Static Brushes.Green}"
                                       Threshold="80" />
            </Binding.Converter>
        </Binding>
    </TextBlock.Foreground>
    <TextBlock.Text>
        <Binding Path="TestDouble">
            <Binding.Converter>
                <vc:ThresholdConverter BelowValue="Repeat"
                                       AboveValue="Successful"
                                       Threshold="80" />
            </Binding.Converter>
        </Binding>
    </TextBlock.Text>
</TextBlock>

public class ThresholdConverter : IValueConverter
{
    public double Threshold { get; set; }

    public object AboveValue { get; set; }
    public object BelowValue { get; set; }

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        double input;
        if (value is double)
        {
            input = (double)value;
        }
        else
        {
            var converter = new DoubleConverter();
            input = (double)converter.ConvertFrom(value);
        }
        return input < Threshold ? BelowValue : AboveValue;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotSupportedException();
    }
}