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INotifyPropertyChanged Interface

Notifies clients that a property value has changed.

Namespace:  System.ComponentModel
Assemblies:   System (in System.dll)
  System.ObjectModel (in System.ObjectModel.dll)

public interface INotifyPropertyChanged

The INotifyPropertyChanged type exposes the following members.

Public eventSupported by the XNA FrameworkSupported by Portable Class LibraryPropertyChangedOccurs when a property value changes.

The INotifyPropertyChanged interface is used to notify clients, typically binding clients, that a property value has changed.

For example, consider a Person object with a property called FirstName. To provide generic property-change notification, the Person type implements the INotifyPropertyChanged interface and raises a PropertyChanged event when FirstName is changed.

For change notification to occur in a binding between a bound client and a data source, your bound type should either:

  • Implement the INotifyPropertyChanged interface (preferred).

  • Provide a change event for each property of the bound type.

Do not do both.

The following code example demonstrates the how to implement the INotifyPropertyChanged interface. When you run this example, you will notice the bound DataGridView control reflects the change in the data source without requiring the binding to be reset.

If you use the CallerMemberName attribute, calls to the NotifyPropertyChanged method don't have to specify the property name as a string argument. For more information, see Caller Information (C# and Visual Basic).

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Runtime.CompilerServices;
using System.Windows.Forms;

// Change the namespace to the project name. 
namespace TestNotifyPropertyChangedCS
    // This form demonstrates using a BindingSource to bind 
    // a list to a DataGridView control. The list does not 
    // raise change notifications. However the DemoCustomer type  
    // in the list does. 
    public partial class Form1 : Form
        // This button causes the value of a list element to be changed. 
        private Button changeItemBtn = new Button();

        // This DataGridView control displays the contents of the list. 
        private DataGridView customersDataGridView = new DataGridView();

        // This BindingSource binds the list to the DataGridView control. 
        private BindingSource customersBindingSource = new BindingSource();

        public Form1()

            // Set up the "Change Item" button.
            this.changeItemBtn.Text = "Change Item";
            this.changeItemBtn.Dock = DockStyle.Bottom;
            this.changeItemBtn.Click +=
                new EventHandler(changeItemBtn_Click);

            // Set up the DataGridView.
            customersDataGridView.Dock = DockStyle.Top;

            this.Size = new Size(400, 200);

        private void Form1_Load(object sender, EventArgs e)
            // Create and populate the list of DemoCustomer objects 
            // which will supply data to the DataGridView.
            BindingList<DemoCustomer> customerList = new BindingList<DemoCustomer>();

            // Bind the list to the BindingSource. 
            this.customersBindingSource.DataSource = customerList;

            // Attach the BindingSource to the DataGridView. 
            this.customersDataGridView.DataSource =


        // Change the value of the CompanyName property for the first  
        // item in the list when the "Change Item" button is clicked.
        void changeItemBtn_Click(object sender, EventArgs e)
            // Get a reference to the list from the BindingSource.
            BindingList<DemoCustomer> customerList =
                this.customersBindingSource.DataSource as BindingList<DemoCustomer>;

            // Change the value of the CompanyName property for the  
            // first item in the list.
            customerList[0].CustomerName = "Tailspin Toys";
            customerList[0].PhoneNumber = "(708)555-0150";


    // This is a simple customer class that  
    // implements the IPropertyChange interface. 
    public class DemoCustomer : INotifyPropertyChanged
        // These fields hold the values for the public properties. 
        private Guid idValue = Guid.NewGuid();
        private string customerNameValue = String.Empty;
        private string phoneNumberValue = String.Empty;

        public event PropertyChangedEventHandler PropertyChanged;

        // This method is called by the Set accessor of each property. 
        // The CallerMemberName attribute that is applied to the optional propertyName 
        // parameter causes the property name of the caller to be substituted as an argument. 
        private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));

        // The constructor is private to enforce the factory pattern. 
        private DemoCustomer()
            customerNameValue = "Customer";
            phoneNumberValue = "(312)555-0100";

        // This is the public factory method. 
        public static DemoCustomer CreateNewCustomer()
            return new DemoCustomer();

        // This property represents an ID, suitable 
        // for use as a primary key in a database. 
        public Guid ID
                return this.idValue;

        public string CustomerName
                return this.customerNameValue;

                if (value != this.customerNameValue)
                    this.customerNameValue = value;

        public string PhoneNumber
                return this.phoneNumberValue;

                if (value != this.phoneNumberValue)
                    this.phoneNumberValue = value;

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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