Programmer's Highway

using System.Data.SqlClient;

    private SqlDependency sqlDependency;
    
    /// <summary>
    /// Query Notification
    /// </summary>
    private void button1_Click(object sender, EventArgs e)
    {
        // Connection Strings
        string connectionString = "Data Source=127.0.0.7;Initial Catalog=TestDatabase;Integrated Security=True;";
    
        // Start SqlDependency.
        SqlDependency.Start(connectionString);
    
        using (SqlConnection sqlConnection = new SqlConnection(connectionString))
        using (SqlCommand sqlCommand = sqlConnection.CreateCommand())
        {
            sqlConnection.Open();
            sqlCommand.CommandText = "SELECT Student.Name, Student.Sex, Student. FROM dbo.Student";
        
            // Register the event handler.
            this.sqlDependency = new SqlDependency(sqlCommand);
            this.sqlDependency.OnChange += OnChange;
        
            // If you need a query, call sqlCommand.ExecuteReader()
            sqlCommand.ExecuteNonQuery();
        }
    }
    
    /// <summary>
    /// Query Notification Event
    /// </summary>
    private void OnChange(object sender, EventArgs e)
    {
        System.Diagnostics.Debug.WriteLine("OnChange");
    
        // If you do not need any more delete event
        this.sqlDependency.OnChange -= OnChange;
    }