Question

Is there an easy way to transform or format a string as part of WPF data binding?

Suppose I want to create a WPF Hyperlink element based on a string tag.

<Hyperlink NavigateUri="{Binding Tag}">
    <Run Text="{Binding Tag}" />
</Hyperlink>

But I need to transform the Tag first for the NavigateUri property to make it a true hyperlink or PackUri.

For instance, if my tag were “folksonomy” I’d want to create a string like: http://www.example.com/tags/tagview?tag=folksonomy

What’s the best way to achieve this? Is there a string manipulation function in XAML? Do I have to write a converter? Do I have to build a whole separate ViewModel class just to do a little string formatting?

UPDATE: There appears to be something strange going on with the Hyperlink element. I can get the StringFormat syntax suggested in the answers to work for the Text property of an ordinary TextBlock, but not for the NavigateUri property of a Hyperlink.

As one answer noted, this is likely due to the fact that the NavigateUri property officially takes a Uri, not a string. Apparently a custom converter or ViewModel property will be required.

Answer 1

You can use the string formatting capabilities of bindings:

<Hyperlink NavigateUri="{Binding Tag, StringFormat=http://www.example.com/tags/tagview?tag={0}}">
    <Run Text="{Binding Tag}" />
</Hyperlink>