What is the proper way to bind Nullable DateTime property to DateTimePicker?

I have an object that I'm trying to bind its properties to two DateTimePicker controls.

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

 

What is the proper way to bind Nullable DateTime Property to DateTimePicker?

There's not really a right way since the DateTimePicker does not have good support for null values. You have a couple of options:

1. You can use a ReadOnly TextBox and a MonthCalendar rather than a DateTimePicker. You'd bind to the TextBox and use the MonthCalendar to set the date in the TextBox.

2. You can use DateTimePicker's null support which is a little clumsy from a UI perspective. This also requires you to write some glue code that maps the DateTimePicker's null representation to a null on your Nullable<DateTime> property. You can do this as follows:

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;
}
}
}
}