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How to: Raise Change Notifications Using a BindingSource and the INotifyPropertyChanged Interface 

The BindingSource component will automatically detect changes in a data source when the type contained in the data source implements the INotifyPropertyChanged interface and raises PropertyChanged events when a property value is changed. This is useful because controls bound to the BindingSource will then automatically update as the data source values change.

NoteNote

If your data source implements INotifyPropertyChanged and you are performing asynchronous operations, you should not make changes to the data source on a background thread. Instead, you should read the data on a background thread and merge the data into a list on the UI thread.

Example

The following code example demonstrates a simple implementation of the INotifyPropertyChanged interface. It also shows how the BindingSource automatically passes a data source change to a bound control when the BindingSource is bound to a list of the INotifyPropertyChanged type.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.Common;
using System.Diagnostics;
using System.Drawing;
using System.Data.SqlClient;
using System.Windows.Forms;

// 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 class Form1 : System.Windows.Forms.Form
{
	// This button causes the value of a list element to be changed.
	private Button changeItemBtn = new Button();

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

	// This is the BindingSource used to bind 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);
		this.Controls.Add(this.changeItemBtn);

		// Set up the DataGridView.
		customersDataGridView.Dock = DockStyle.Top;
		this.Controls.Add(customersDataGridView);
		this.Size = new Size(800, 200);
		this.Load += new EventHandler(Form1_Load);
	}

	private void Form1_Load(System.Object sender, System.EventArgs e)
	{
		// Create and populate the list of DemoCustomer objects
		// which will supply data to the DataGridView.
		List<DemoCustomer> customerList = new List<DemoCustomer>();
		customerList.Add(DemoCustomer.CreateNewCustomer());
		customerList.Add(DemoCustomer.CreateNewCustomer());
		customerList.Add(DemoCustomer.CreateNewCustomer());

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

		// Attach the BindingSource to the DataGridView.
		this.customersDataGridView.DataSource =
			this.customersBindingSource;
	}

	// This event handler changes the value of the CompanyName
	// property for the first item in the list.
	void changeItemBtn_Click(object sender, EventArgs e)
	{
		// Get a reference to the list from the BindingSource.
		List<DemoCustomer> customerList =
			this.customersBindingSource.DataSource as List<DemoCustomer>;

		// Change the value of the CompanyName property for the 
		// first item in the list.
		customerList[0].CompanyName = "Tailspin Toys";

	}

	

	[STAThread]
	static void Main()
	{
		Application.EnableVisualStyles();
		Application.Run(new Form1());
	}
}

// This class implements a simple customer type 
// 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 customerName = String.Empty;
	private string companyNameValue = String.Empty;
	private string phoneNumberValue = String.Empty;

	public event PropertyChangedEventHandler PropertyChanged;
	
	private void NotifyPropertyChanged(String info)
	{
		if (PropertyChanged != null)
		{
			PropertyChanged(this, new PropertyChangedEventArgs(info));
		}
	}

	// The constructor is private to enforce the factory pattern.
	private DemoCustomer()
	{
		customerName = "no data";
		companyNameValue = "no data";
		phoneNumberValue = "no data";
	}

	// 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
	{
		get
		{
			return this.idValue;
		}
	}

	public string CompanyName
	{
		get
		{
			return this.companyNameValue;
		}

		set
		{
            if (value != this.companyNameValue)
            {
                this.companyNameValue = value;
                NotifyPropertyChanged("CompanyName");
            }
		}
	}

	public string PhoneNumber
	{
		get
		{
			return this.phoneNumberValue;
		}

		set
		{
            if (value != this.phoneNumberValue)
            {
                this.phoneNumberValue = value;
                NotifyPropertyChanged("PhoneNumber");
            }
		}
	}
}

Compiling the Code

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