WPF - How do I default the Visibility of a databound Textblock?

wpf default visibility textblock databound
empo picture empo · Nov 11, 2009 · Viewed 10.1k times · Source

This Textblock, defined below, shows when the window first loads because it has no Datacontext (and hence the converter code is not run) until an item has been selected from another control e.g. TreeView.

<TextBlock
   Name="tbkDocumentNotFound" 
   Style="{StaticResource StandardText}"
   Margin="4,4,2,0" 
   TextWrapping="Wrap"                                    
   Visibility="{Binding Path=IsDownloaded, Converter={StaticResource docNotFoundVisibilityConverter}, Mode=TwoWay}"
   Text="The document could not be found.">
</TextBlock>

So how do I stop the it from appearing when it has no DataContext?

Thanks.

Answer

GraemeF picture GraemeF · Nov 11, 2009

To provide a default value (used when the target of a Binding can't be found) you use the FallbackValue, for example:

Visibility="{Binding Path=IsDownloaded, FallbackValue=Collapsed}"

This should be the case when there is no DataContext.

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