使用 XAML 中的转换器更改背景颜色

Question

TextBlock background color not changing.

I've bound my data to a TextBlock which updates with INotifyPropertyChanged , and the converter does fire.

public class Oddsindicator : IMultiValueConverter
{

    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        string myPrice = "0";
        string tradePrice = "0";

        var colorRed = (System.Windows.Media.Color)System.Windows.Media.ColorConverter.ConvertFromString("#FFB0E0E6");
        var colorWhite = (System.Windows.Media.Color)System.Windows.Media.ColorConverter.ConvertFromString("White");

        var unchanged = new SolidColorBrush(colorRed);
        var changed = new SolidColorBrush(colorGreen);

        if (values[0] != DependencyProperty.UnsetValue)
        {
            myPrice = values[0].ToString();
            tradePrice = values[1].ToString();
        }

        if (myPrice == tradePrice)
        {
            return unchanged;
        }
        else
        {
            return changed;
        }
    }
}

XAML:

<Window.Resources>

    <local:Oddsindicator x:Key="Oddsindicator" >

    </local:Oddsindicator>

</Window.Resources>

<TextBlock Text="{Binding BackPrice, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"  TextAlignment="Center" Margin="1"  Grid.Row="4" Grid.Column="2" />
<TextBlock>
    <TextBlock.Background>
        <MultiBinding Converter="{StaticResource Oddsindicator}">

            <Binding Path="BackPrice"/>
            <Binding Path="Lasttradedprice" />

        </MultiBinding>
    </TextBlock.background>
</TextBlock>

I've used break points at the return and they both fire. My bound value updates perfectly. The converters comparing the values and giving the correct results, just not updating the TextBlock .

Answer 1

(This should in fact be a comment but I need the formatting features of an answer)

You have two TextBlocks. The second (for which you set the background) has no Text and is probably of 0 size. Try putting the TextBlock.Background in the first TextBlock:

<TextBlock Text="{Binding BackPrice, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"  TextAlignment="Center" Margin="1"  Grid.Row="4" Grid.Column="2" >
    <TextBlock.Background>
        <MultiBinding Converter="{StaticResource Oddsindicator}">
            <Binding Path="BackPrice"/>
            <Binding Path="Lasttradedprice" />
        </MultiBinding>
    </TextBlock.Background>
</TextBlock>