One of the most common scenarios for using the DataGridView control is the master/detail form, in which a parent/child relationship between two database tables is displayed. Selecting rows in the master table causes the detail table to update with the corresponding child data.

Implementing a master/detail form is easy using the interaction between the DataGridView control and the BindingSource component. The below sample will show two related tables in the Northwind SQL Server sample database: Customers and Orders. By selecting a customer in the master DataGridView all the orders for the customer will appear in the detail DataGridView.

using System;
using System.Data;
using System.Data.SqlClient;
using System.Windows.Forms;
public class Form1 : System.Windows.Forms.Form
{
  private DataGridView masterDataGridView = new DataGridView();
  private BindingSource masterBindingSource = new BindingSource();
  private DataGridView detailsDataGridView = new DataGridView();
  private BindingSource detailsBindingSource = new BindingSource();

  [STAThreadAttribute()]
  public static void Main()
  {
    Application.Run(new Form1());
  }

  // Initializes the form.
  public Form1()
  {
    masterDataGridView.Dock = DockStyle.Fill;
    detailsDataGridView.Dock = DockStyle.Fill;
    SplitContainer splitContainer1 = new SplitContainer();
    splitContainer1.Dock = DockStyle.Fill;
    splitContainer1.Orientation = Orientation.Horizontal;
    splitContainer1.Panel1.Controls.Add(masterDataGridView);
    splitContainer1.Panel2.Controls.Add(detailsDataGridView);
    this.Controls.Add(splitContainer1);
    this.Load += new System.EventHandler(Form1_Load);
    this.Text = "DataGridView master/detail demo";
  }

  private void Form1_Load(object sender, System.EventArgs e)
  {
    // Bind the DataGridView controls to the BindingSource
    // components and load the data from the database.
    masterDataGridView.DataSource = masterBindingSource;
    detailsDataGridView.DataSource = detailsBindingSource;
    GetData();
    // Resize the master DataGridView columns to fit the newly loaded data.
    masterDataGridView.AutoResizeColumns();
    // Configure the details DataGridView so that its columns automatically
    // adjust their widths when the data changes.
    detailsDataGridView.AutoSizeColumnsMode =
    DataGridViewAutoSizeColumnsMode.AllCells;
  }

  private void GetData()
  {
    try
    {
      // Specify a connection string. Replace the given value with a 
      // valid connection string for a Northwind SQL Server sample
      // database accessible to your system.
      String connectionString =
      "Integrated Security=SSPI;Persist Security Info=False;" +
      "Initial Catalog=Northwind;Data Source=localhost";
      SqlConnection connection = new SqlConnection(connectionString);
      // Create a DataSet.
      DataSet data = new DataSet();
      data.Locale = System.Globalization.CultureInfo.InvariantCulture;
      // Add data from the Customers table to the DataSet.
      SqlDataAdapter masterDataAdapter = new
      SqlDataAdapter("select * from Customers", connection);
      masterDataAdapter.Fill(data, "Customers");
      // Add data from the Orders table to the DataSet.
      SqlDataAdapter detailsDataAdapter = new
      SqlDataAdapter("select * from Orders", connection);
      detailsDataAdapter.Fill(data, "Orders");
      // Establish a relationship between the two tables.
      DataRelation relation = new DataRelation("CustomersOrders",
      data.Tables["Customers"].Columns["CustomerID"],
      data.Tables["Orders"].Columns["CustomerID"]);
      data.Relations.Add(relation);
      // Bind the master data connector to the Customers table.
      masterBindingSource.DataSource = data;
      masterBindingSource.DataMember = "Customers";
      // Bind the details data connector to the master data connector,
      // using the DataRelation name to filter the information in the 
      // details table based on the current row in the master table. 
      detailsBindingSource.DataSource = masterBindingSource;
      detailsBindingSource.DataMember = "CustomersOrders";
    }
    catch (SqlException)
    {
      MessageBox.Show("To run this example, replace the value of the " +
        "connectionString variable with a connection string that is " +
        "valid for your system.");
    }
  }
}