WPF Binding with StringFormat

Question

Could anyone explain to me why this does not render "VALUE IS DEFAULT"?

<TextBlock Text="{Binding Fail, StringFormat=VALUE IS {0}, FallbackValue=DEFAULT}" />

There is something tricky about this syntax I am missing. Thank you in advance.

decyclone · Accepted Answer · 2011-05-03 17:22:07Z

7

Binding in WPF does not consider StringFormat while falling back to FallbackValue in case it fails.

You can use what leon suggested or go with PriorityBinding.

--EDIT--

This should work:

<TextBlock DataContext="{Binding Fail, FallbackValue=DEFAULT}" Text="{Binding StringFormat=VALUE IS {0}}" />

answered May 3, 2011 at 16:52

decyclone

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Comments

Gerrrard · Accepted Answer · 2011-05-04 07:36:33Z

1

I think it could also work using the runs inside the TextBlock :

     <TextBlock>
             <Run Text="Value is : "/>
             <Run Text="{Binding Fail,FallbackValue=Default}"/>
     </TextBlock>

?

answered May 4, 2011 at 7:36

Gerrrard

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leon.io · Accepted Answer · 2011-05-03 16:43:30Z

0

The default fallback value is used for priority bindings, if you'd like to display "VALUE IS DEFAULT" for a fallback value, try the following.

<TextBlock Text="{Binding Fail, StringFormat=VALUE IS {0}, FallbackValue='VALUE IS DEFAULT'}" />

answered May 3, 2011 at 16:43

leon.io

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Do you mean if the FallbackBinding is used the StringFormat is not?

Yes, I have verified that StringFormat is ignored when FallbackValue