#355 – Implementing Three-State CheckBox Dependent Behavior

You can use a three-state CheckBox to reflect the state of a set of other CheckBox controls.

Here’s some sample code that implements this behavior.  (See the previous post for the XAML).

    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        private bool doEat;
        public bool DoEat
        {
            get { return doEat; }
            set
            {
                doEat = value;
                OnPropertyChanged("DoEat");
                OnPropertyChanged("DoEverything");
            }
        }

        // Add same code for DoPray and DoLove properties here

        // Nullable bool - can be true, false or null
        public bool? DoEverything
        {
            get
            {
                if (DoEat && DoPray && DoLove)
                    return true;
                else if (!DoEat && !DoPray && !DoLove)
                    return false;
                else
                    return null;
            }

            set
            {
                if (value == true)
                    DoEat = DoPray = DoLove = true;
                else
                    DoEat = DoPray = DoLove = false;
            }
        }

        public MainWindow()
        {
            this.InitializeComponent();
            this.DataContext = this;
        }

        private void OnPropertyChanged(string prop)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(prop));
        }
    }

About Sean
Software developer in the Twin Cities area, passionate about .NET technologies. Equally passionate about my own personal projects related to family history and preservation of family stories and photos.

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