Почему вылетает исключение ???

using System;
using System.IO;
using System.Windows.Forms;
using System.Xml.Serialization;
 
public class Person
{
    string strFirstName, strLastName;
    private DateTime dtBirth = new DateTime(1800, 1, 1);
 
    public string FirstName
    {
        get { return strFirstName; }
        set { strFirstName = value; }
    }
    public string LastName
    {
        get { return strLastName; }
        set { strLastName = value; }
    }
    public DateTime BirthDate
    {
        get { return dtBirth; }
        set { dtBirth = value; }
    }
}
 
class MyDateTimePicker : DateTimePicker
{
    new public DateTime Value
    {
        get { return base.Value; }
        set
        {
            Console.WriteLine("Value == : " + value); //Почему здесь value == DateTime.MinDate ???
            base.Value = value;
        }
    }
}
 
class PersonPanelWithBinding : FlowLayoutPanel
{
    TextBox txtboxFirstName, txtboxLastName;
    DateTimePicker dtPicker;
    Person pers = new Person();
 
    public PersonPanelWithBinding()
    {
        Label lbl = new Label();
        lbl.Parent = this;
        lbl.Text = "First Name: ";
        lbl.AutoSize = true;
        lbl.Anchor = AnchorStyles.Left;
 
        txtboxFirstName = new TextBox();
        txtboxFirstName.Parent = this;
        txtboxFirstName.AutoSize = true;
        txtboxFirstName.DataBindings.Add("Text", pers, "FirstName");
 
        this.SetFlowBreak(txtboxFirstName, true);
 
        lbl = new Label();
        lbl.Parent = this;
        lbl.Text = "Last Name: ";
        lbl.AutoSize = true;
        lbl.Anchor = AnchorStyles.Left;
 
        txtboxLastName = new TextBox();
        txtboxLastName.Parent = this;
        txtboxLastName.AutoSize = true;
        txtboxLastName.DataBindings.Add("Text", pers, "LastName");
 
        this.SetFlowBreak(txtboxLastName, true);
 
        lbl = new Label();
        lbl.Parent = this;
        lbl.Text = "Birth Date: ";
        lbl.AutoSize = true;
        lbl.Anchor = AnchorStyles.Left;
 
        dtPicker = new MyDateTimePicker();
        dtPicker.Parent = this;
        dtPicker.Format = DateTimePickerFormat.Long;
        dtPicker.AutoSize = true;
        dtPicker.DataBindings.Add("Value", pers, "BirthDate");
    }
 
    public Person Person
    {
        set
        {
            pers.FirstName = value.FirstName;
            pers.LastName = value.LastName;
            pers.BirthDate = value.BirthDate;
 
            foreach (Control ctrl in Controls)
                foreach (Binding bind in ctrl.DataBindings)
                    bind.ReadValue();
        }
        get { return pers; }
    }
}
 
class DataEntryNoBinding : Form
{
    [STAThread]
    public static void Main()
    {
        Application.EnableVisualStyles();
        Application.Run(new DataEntryNoBinding());
    }
 
    const string strFilter = "Person XML files (*.PersonXml)|" +
                         "*.PersonXml|All files (*.*)|*.*";
 
    PersonPanelWithBinding personpnl;
    XmlSerializer xmlser = new XmlSerializer(typeof(Person));
 
    public DataEntryNoBinding()
    {
        personpnl = new PersonPanelWithBinding();
        personpnl.Parent = this;
        personpnl.Dock = DockStyle.Fill;
 
        MenuStrip menu = new MenuStrip();
        menu.Parent = this;
        ToolStripMenuItem item = (ToolStripMenuItem)menu.Items.Add("&File");
        item.DropDownItems.Add("&New", null, FileNewOnClick);
        item.DropDownItems.Add("&Open...", null, FileOpenOnClick);
        item.DropDownItems.Add("Save &As...", null, FileSaveAsOnClick);
 
        FileNewOnClick(this, EventArgs.Empty);
    }
 
    protected override void OnLoad(EventArgs args)
    {
        base.OnLoad(args);
 
        Text = "MyBinding";
    }
 
    void FileNewOnClick(object objSrc, EventArgs args)
    {
        personpnl.Person = new Person();
    }
 
    void FileOpenOnClick(object objSrc, EventArgs args)
    {
        OpenFileDialog dlg = new OpenFileDialog();
        dlg.Filter = strFilter;
 
        if (dlg.ShowDialog() == DialogResult.OK)
        {
            using (StreamReader sr = new StreamReader(dlg.FileName))
            {
                personpnl.Person = xmlser.Deserialize(sr) as Person;
            }
        }
    }
 
    void FileSaveAsOnClick(object objSrc, EventArgs args)
    {
        SaveFileDialog dlg = new SaveFileDialog();
        dlg.Filter = strFilter;
 
        if (dlg.ShowDialog() == DialogResult.OK)
        {
            using (StreamWriter sw = new StreamWriter(dlg.FileName))
            {
                xmlser.Serialize(sw, personpnl.Person);
            }
        }
    }
}

foreach (Control ctrl in Controls)
foreach (Binding bind in ctrl.DataBindings)
bind.ReadValue();