Hide multibinding stringformat when binding returns null

Question

I was looking to bind a timespan property to a textblock,which seems to be resolved with the help of this post

Now i want to hide StringFormat when data is null.From the thread if i use a mutibinding with a stringformat and if my data is null then the stringformat displays just a ":"

<TextBlock>
    <TextBlock.Text>
        <MultiBinding StringFormat="{}{0}:{1}">
            <Binding Path="MyTime.Hours" TargetNullValue={x:Null}/>
            <Binding Path="MyTime.Minutes" TargetNullValue={x:Null}/>
        </MultiBinding>
    </TextBlock.Text>
</TextBlock>

How could i hide the ":" if data is null

score 5 · Accepted Answer · answered Dec 30 '10 at 17:15

I'm basically answering the same thing as Nicolas Repiquet here but anyway..
It feels like there is a part missing in the framework here. There is no way (as far as I know) to make a MultiBinding use a FallbackValue without a Converter. Using this approach will probably set you back to square 1 since your last question was about a better approach then using a Converter :)

<TextBlock>
    <TextBlock.Text>
        <MultiBinding StringFormat="{}{0}:{1}"
                      Converter="{StaticResource FallbackConverter}"
                      FallbackValue="">
            <Binding Path="MyTime.Hours" />
            <Binding Path="MyTime.Minutes" />
        </MultiBinding>
    </TextBlock.Text>
</TextBlock>

And the Converter basically does what you "should" be able to use a Property for

public class FallbackConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        foreach (object value in values)
        {
            if (value == DependencyProperty.UnsetValue)
            {
                return DependencyProperty.UnsetValue;
            }
        }
        return values;
    }
    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Looks like it is not such a bad idea to go with a converter ;) — biju, Dec 31 '10 at 02:34

score 2 · Answer 2 · edited May 23 '17 at 11:55

2

Take a look at multibinding fallback value here.

edited May 23 '17 at 11:55

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answered Dec 30 '10 at 16:29

Nicolas Repiquet

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Hide multibinding stringformat when binding returns null

2 Answers2