BingMainPage.cs

public class BingMainPage
{
    private readonly IWebDriver driver;
    private readonly string url = @"http://www.bing.com/";

    public BingMainPage(IWebDriver browser)
    {
        this.driver = browser;
        PageFactory.InitElements(browser, this);
    }

    public string Url => @"http://www.bing.com/";

    [FindsBy(How = How.Id, Using = "sb_form_q")]
    public IWebElement SearchBox { get; set; }

    [FindsBy(How = How.Id, Using = "sb_form_go")]
    public IWebElement GoButton { get; set; }

    [FindsBy(How = How.Id, Using = "b_tween")]
    public IWebElement ResultsCountDiv { get; set; }

    public void Navigate() => this.driver.Navigate().GoToUrl(this.url);

    public void Search(string textToType)
    {
        this.SearchBox.Clear();
        this.SearchBox.SendKeys(textToType);
        this.GoButton.Click();
    }

    public void AssertResultsCount(string expectedCount) => Assert.AreEqual(this.ResultsCountDiv.Text, expectedCount);
}