Example Program

    public partial class Form1 : Form
    {
        DataComponent dc;
        public Form1()
        {
            InitializeComponent();
            dc = new DataComponent();
            checkBox1.CheckedChanged += (s, e) => { customControl1.Text = "3"; label1.Text = dc.BooleanVal.ToString(); };
            button1.Click += (s, e) => { dc.BooleanVal = !dc.BooleanVal; label1.Text = dc.BooleanVal.ToString(); };
        }
        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);
            checkBox1.DataBindings.Add("Checked", dc, "BooleanVal", false, DataSourceUpdateMode.OnPropertyChanged);

            customControl1.DataBindings.Add("BaseValue", dc, "FloatVal", false, DataSourceUpdateMode.OnPropertyChanged);
        }
    }

    class CustomControl : TextBox, INotifyPropertyChanged
    {
        public override string Text
        {
            get
            {
                return base.Text;
            }
            set
            {
                base.Text = value;
                float s;
                if (!float.TryParse(value, out s))
                    s = 0.0f;
                this.BaseValue = s;
            }
        }
        public float BaseValue
        {
            get { return baseValue; }
            set
            {
                baseValue = value;
                this.OnPropertyChanged("BaseValue");
            }
        }
        float baseValue;
        public void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;
    }

    class DataComponent : INotifyPropertyChanged
    {
        public DataComponent()
        {
        }
        public bool BooleanVal
        {
            get { return boolExample; }
            set {
                boolExample = value;
                this.OnPropertyChanged("BooleanVal");
            }
        }
        public float FloatVal
        {
            get { return valExample; }
            set
            {
                valExample = value;
                this.OnPropertyChanged("FloatVal");
            }
        }
        bool boolExample = false;
        float valExample = 0.0f;

        public void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;
    }