Question

There are two TextBox on the WPF page. While user is typing into the first TextBox, the second TextBox must display modified text from the first TextBox. As a result both values must be binded to a view model.

Can it be done with Data Binding?

I was able to get the second TextBox display text from the first one implementing DependencyProperty on my view model. But I don’t have the slightest idea how to apply transformation on the fly.

Maybe there is an easy way to achieve this?

Answer 1

Just use databinding with UpdateSourceTrigger set to PropertyChanged:

<TextBox x:Name='txt1' Text="{Binding MyText, UpdateSourceTrigger=PropertyChanged}" />
<TextBox x:Name='txt2' Text="{Binding MyText, UpdateSourceTrigger=PropertyChanged}" />

In this case it will update ViewModel’s property on the fly instead of waiting for FocusLost.