Page changing example in c#

public class LoginPage

{

    private IWebDriver driver;

    private By usernameLocator = By.Id("username");

    private By passwordLocator = By.Id("password");

    private By loginButtonLocator = By.Id("login");

    public LoginPage(IWebDriver driver)

    {

        this.driver = driver;

    }

    public void EnterUsername(string username)

    {

        driver.FindElement(usernameLocator).SendKeys(username);

    }

    public void EnterPassword(string password)

    {

        driver.FindElement(passwordLocator).SendKeys(password);

    }

    public DashboardPage ClickLoginButton()

    {

        driver.FindElement(loginButtonLocator).Click();

        return new DashboardPage(driver);

    }

}

public class DashboardPage

{

    private IWebDriver driver;

    private By welcomeMessageLocator = By.Id("welcome-message");

    public DashboardPage(IWebDriver driver)

    {

        this.driver = driver;

    }

    public string GetWelcomeMessage()

    {

        return driver.FindElement(welcomeMessageLocator).Text;

    }

}

public class LoginTests

{

    private IWebDriver driver;

    [SetUp]

    public void SetUp()

    {

        driver = new ChromeDriver();

        driver.Manage().Window.Maximize();

    }

    [Test]

    public void TestSuccessfulLogin()

    {

        LoginPage loginPage = new LoginPage(driver);

        DashboardPage dashboardPage = loginPage.EnterUsername("admin")

                                               .EnterPassword("password")

                                               .ClickLoginButton();

        string welcomeMessage = dashboardPage.GetWelcomeMessage();

        Assert.AreEqual("Welcome, admin!", welcomeMessage);

    }

    [TearDown]

    public void TearDown()

    {

        driver.Quit();

    }

}