class Order
{
public DateTime OrderPlacedDate { get; }
public Nullable<DateTime> ShippedDate { get; }
}

Customer _customer; // Has a Nullable<DateTime> property called "HireDate"

private void Form1_Load(object sender, EventArgs e)
{
// Create Customer
_customer = new Customer("555", "John Doe", 1000, DateTime.Now);

// Bind
Binding binding = new Binding("Value", _customer, "HireDate", true);
this.dateTimePicker1.DataBindings.Add(binding);

// BindingComplete
binding.Format += new ConvertEventHandler(Binding_Format);
binding.Parse += new ConvertEventHandler(Binding_Parse);
}

void Binding_Parse(object sender, ConvertEventArgs e)
{
// Need to make the Control show NULL
Binding binding = sender as Binding;

if (null != binding)
{
DateTimePicker dtp = (binding.Control as DateTimePicker);

if ((null != dtp) && (dtp.Checked))
e.Value = new Nullable<DateTime>();
}
}

void Binding_Format(object sender, ConvertEventArgs e)
{
INullableValue inv = (e.Value as INullableValue);

if ((null != inv) && (!inv.HasValue))
{
// Need to make the Control show NULL
Binding binding = sender as Binding;

if (null != binding)
{
DateTimePicker dtp = (binding.Control as DateTimePicker);

if (null != dtp)
{
dtp.ShowCheckBox = true;
dtp.Checked = false;
e.Value = dtp.Value;
}
}
}
}