Export (0) Print
Expand All

How to: Raise Change Notifications Using the BindingSource ResetItem Method

Some data sources for your controls do not raise change notifications when items are changed, added, or deleted. With the BindingSource component, you can bind to such data sources and raise a change notification from your code.

This form demonstrates using a BindingSource component to bind a list to a DataGridView control. The list does not raise change notifications, so the ResetItem method on the BindingSource is called when an item in the list is changed. .

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, so the ResetItem method  
// on the BindingSource is used. 
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);

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

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

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

    // 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";

        // Call ResetItem to alert the BindingSource that the  
        // list has changed. 

    static void Main()
        Application.Run(new Form1());

// This class implements a simple customer type. 
public class DemoCustomer
    // 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;

    // 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
            return this.idValue;

    public string CompanyName
            return this.companyNameValue;

            this.companyNameValue = value;

    public string PhoneNumber
            return this.phoneNumberValue;

            this.phoneNumberValue = value;

This example requires:

  • References to the System, System.Data, System.Drawing and System.Windows.Forms assemblies.

For information about building this example from the command line for Visual Basic or Visual C#, see Building from the Command Line (Visual Basic) or Command-line Building With csc.exe. You can also build this example in Visual Studio by pasting the code into a new project. Also see How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio.

© 2014 Microsoft