Question

May someone tell me whats wrong with this sourcecode?
when i click the button its not updating ist value?
At first binding the converter makes his job.

the sourcecode is pretty big so i will post only some snippets.

XAML:
Instances is type of ObservableCollection

<ListBox Name="Instances">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <Button Tag="{Binding Path=Instance.Name}" Content="{Binding Path=Instance.Active, Converter={StaticResource BTSC}}" Click="ChangeAccess"/>
            <TextBlock Text="{Binding Path=Instance.Name}"/>
         </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

Converter:

public class BoolToStringConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (((Boolean)value) == true)
            return "No";
        else
            return "Yes";
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
} 

Event:

private void ChangeAccess(object sender, RoutedEventArgs e)
{
    for...
    if ((sender as Button).Tag.ToString() == (DP.Instances[i].Instance as CInstance).Name)
    {
        SkipIfAndElse...
        DP.Instances[i].Instance.Active = true;
    }
}

CInstance:

class CInstance : INotifyPropertyChanged
{
    private Boolean active;
    public Boolean Active
    {
        get { return active; }
        set
        {
            active = value;
            NotifyPropertyChanged("Access");
        }
    }
}

All other values of the CInstance class are updating as expected.

Answer 1

In your CInstance class

NotifyPropertyChanged("Access");

should be

NotifyPropertyChanged("Active");