Subscribing to PropertyChangedEventHandler in Winforms - winforms

Question

In the following example the temp variable in RaisePropertyChanged() is always null. How do I subscribe to the event?
using System;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations.Schema;
using System.Runtime.CompilerServices;
using System.Text;
namespace TestProject.Module.BusinessObjects
{
public class ContactPerson : INotifyPropertyChanged
{
public string FirstName { get; set; }
public string LastName { get; set; }
[NotMapped]
public string PersonFullName
{
set
{
if (PersonFullName != value)
{
var stringArray = value.Split();
var firstIndex = 0;
var lastIndex = stringArray.Length - 1;
if (lastIndex >= firstIndex)
{
FirstName = stringArray[firstIndex];
}
if (lastIndex > firstIndex)
{
LastName = stringArray[lastIndex];
}
RaisePropertyChanged();
}
}
get
{
var sb = new StringBuilder();
sb.Append(FirstName);
sb.Append(" ");
sb.Append(LastName);
var stringArray = sb.ToString().Split(new[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries);
var s = string.Join(" ", stringArray);
return s;
}
}
public event PropertyChangedEventHandler PropertyChanged;
public ContactPerson Clone()
{
var obj = new ContactPerson { FirstName = FirstName, LastName = LastName };
return obj;
}
public override string ToString()
{
return PersonFullName;
}
protected void RaisePropertyChanged([CallerMemberName] string propertName = "")
{
var temp = PropertyChanged;
if (temp != null)
{
temp(this, new PropertyChangedEventArgs(propertName));
}
}
}
}
from reading This question it seems that PropertyChanged has not been subscribed to. How do I do this subscription?

Answer 1

Like this:
private void Form1_Load(object sender, EventArgs e)
{
ContactPerson p = new ContactPerson();
p.PropertyChanged += P_PropertyChanged;
}
private void P_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
throw new NotImplementedException();
}
EDIT: expanding the sample code:
public partial class Form1 : Form
{
ContactPerson p;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
p = new ContactPerson();
p.PersonFullName = "Mary Jane";
p.PropertyChanged += P_PropertyChanged;
label1.Text = p.PersonFullName;
// If you use databinding instead, you get the same result in this case.
//label1.DataBindings.Add(new Binding("Text", p, "PersonFullName"));
}
private void P_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
label1.Text = p.PersonFullName;
}
private void button1_Click(object sender, EventArgs e)
{
p.PersonFullName = "John Doe";
}
}