[2.0] Binding to my NullableDateTimePicker control

[wey97]

With the addition of Nullable Types to C# 2.0, I wrote my own NullableDateTimePicker control in very few lines of code, as opposed to the nullable DateTimePicker controls I've found that were written for C# 1.1.

public partial class NullableDateTimePicker : DateTimePicker
{
    private DateTime? dtNullable;
 
    public NullableDateTimePicker()
    {
        base.Format = DateTimePickerFormat.Custom;
        base.CustomFormat = " ";
    }
 
    public new DateTime? Value
    {
 
        get
        {
            if (dtNullable.HasValue)
                return base.Value;
 
            return null;
        }
 
        set
        {
            if (value == null)
                dtNullable = null;
            else
                dtNullable = base.Value = value.Value;
 
            OnValueChanged(EventArgs.Empty);
        }
    }
 
    protected override void OnValueChanged(EventArgs eventargs)
    {
 
        if (this.dtNullable.HasValue)
        {
            base.Format = DateTimePickerFormat.Short;
        }
        else
        {
            base.Format = DateTimePickerFormat.Custom;
            base.CustomFormat = " ";
        }
 
        base.OnValueChanged(eventargs);
    }
 
    protected override void OnCloseUp(EventArgs eventargs)
    {
        if (Control.MouseButtons == MouseButtons.None)
        {
            this.Value = base.Value;
        }
 
        base.OnCloseUp(eventargs);
    }
}

Which is alright except if I bind the Value property and the binding source returns a DBNull.Value then I get the following error:

Invalid cast from 'System.DateTime' to 'System.Nullable`

How can I represent a DateTime so that it may contain a valid DateTime, and instead of null, DBNull.Value?