Question

I have two buttons in my application

Now I want to bind the btnOff to !isOn. Meaning is btnOn is Enabled, btnOff should be Disabled and vice-versa

EDIT: Below is my implementation:

<Button x:Name="btnOn" Content="On" Width="45" Height="24" IsEnabled="{Binding isOn, Converter={StaticResource BoolInverter}}" />
   <Button x:Name="btnOff" Content="Off" Width="45" Height="24" IsEnabled="{Binding isOn} />

 public class BoolInverterConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (value is bool)
            {
                return !(bool)value;
            }
            return value;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (value is bool)
            {
                return !(bool)value;
            }
            return value;
        }

    }

Answer 1

Wouldn’t it be simpler to have another computed/derived property IsOff (no backing field) that negates the IsOn property ?

public bool IsOn{ 
  get{...}
  set
  {    _isOn = value; 
       NotifyPropertyChanged("IsOn");
       NotifyPropertyChanged("IsOff");
  }
}

public bool IsOff
{
   get{   return !IsOn;}
}

Converters are normally used to convert data types e.g. to bind a Visibility enum property to a boolean backing property in the viewmodel.