Question

I have text field that binding with int property ProductPrice and button that is disabled if I put in textbox some wrong data (e.g. number that <= 0):

<TextBox Grid.Row="4" Grid.Column="2"
                 Text="{Binding ProductPrice, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged}"
                 Validation.ErrorTemplate="{StaticResource ValidationErrorTemplate}"/>

        <Button HorizontalAlignment="Right" Command="{Binding Path=DataContext.AddProductCommand,
            RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}"
                Margin="2" Width="60" Grid.Row="6" Grid.Column="2" Content="Add" />

But if I put in textbox some text then button is not disabled. I think it because property ProductPrice is not changed because was generate some exception. Herewith validation work normal. What should I do?

Answer 1

Try to set {Binding ProductPrice Mode=TwoWay}

BTW, which exception are thrown?

EDIT: Answer to the comments

I see two options which you are have:

1. Introduce string ProductPriceValue property (under the cover use original one of int type) and bind textbox to it
2. Implement IValueConverter and use it in binding

Just wondering why you’re not using double type for ProductPrice property