Question

I want to increase Progress-bar value based on two textbox’s Text. I wrote this XAML but there is an error “Two-way binding requires path or xpath” when I do MultiBinding in ProgressBar.Value

<Window.Resources>
    <local:Class1 x:Key="ConverterM"/>
</Window.Resources>

<TextBox Height="23" HorizontalAlignment="Left" Margin="157,59,0,0"
         Name="textBox1"  VerticalAlignment="Top" Width="120" />
<TextBox Height="23" HorizontalAlignment="Left" Margin="157,108,0,0"
         Name="textBox2" VerticalAlignment="Top" Width="120" />
<ProgressBar Height="24" HorizontalAlignment="Left" Margin="120,160,0,0"
             Name="progressBar1" VerticalAlignment="Top" Width="243" >
    <ProgressBar.Value>
        <MultiBinding Converter="{StaticResource ConverterM}">
            <Binding />
            <Binding ElementName="textBox1" Path="Text" />
            <Binding ElementName="textBox2" Path="Text" />
        </MultiBinding>
    </ProgressBar.Value>
</ProgressBar>

Value Converter:

public class Class1 : IMultiValueConverter
{
    public object Convert(object[] values,
                          Type targetType,
                          object parameter,
                          System.Globalization.CultureInfo culture)
    {
        if (values[1] != null && values[2]!=null)
        {
            if (((string)values[1]).Length==((string)values[2]).Length)
            {
                return 5.0;
            }
        }
        else
        {
            return 0.0;
        }
    }

    public object[] ConvertBack(object value,
                                Type[] targetTypes,
                                object parameter,
                                System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Answer 1

I think that <Binding /> is not necessary. try to delete it and change indexes in converter.