Here is an example of a bindable DateTimePicker with NULL binding support.

It is just a fw lines of code, so no need to download... Just copy and paste. ;)

Hope it helps

Duray AKAR

    public class DateTimePickerNullable: System.Windows.Forms.DateTimePicker, INotifyPropertyChanged
    {
        public DateTimePickerNullable()
            : base()
        {
            ShowCheckBox = true;
        }

        [Bindable(true)]
        public Nullable<DateTime> BindableValue
        {
            get
            {
                if (Checked)
                {
                    return Value;
                }
                else
                {
                    return null;
                }
            }
            set
            {
                if (value.HasValue && value.Value > DateTime.MinValue)
                {
                    this.Checked = true;
                }
                else
                {
                    this.Checked = false;
                }
            }
        }

        public new bool Checked
        {
            get { return base.Checked; }
            set
            {
                base.Checked = value;
                OnPropertyChanged("BindableValue");
            }
        }

        protected override void OnCloseUp(EventArgs eventargs)
        {
            base.OnCloseUp(eventargs);
            OnPropertyChanged("BindableValue");
        }

        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged!=null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); 
            }
        }

        #endregion
    }