How to work with Selenium Webdriver iFrames

SeleniumIframe.cs

using System;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using OpenQA.Selenium;
using OpenQA.Selenium.Firefox;
using OpenQA.Selenium.Support.UI;

namespace SeleniumWebdriverTips
{

    [TestClass]
    public class RandomSeleniumTricks
    {
        private static LanguageType GetLanguageInUse(string content, 
                                                     LanguageType expectedLanguage = LanguageType.NoLanguageDetermined)
        {
            content = content.Trim();
            var language = DetermineLanguage(content);
            if (language != expectedLanguage && expectedLanguage != LanguageType.NoLanguageDetermined)
                language = OverrideUnexpectedLanguage(content, expectedLanguage);
            return language;
        }
        IWebDriver _driver = new FirefoxDriver();
        WebDriverWait _wait;

        [TestMethod]
        public void IFrames()
        {
            //create an instance of the WebDriverWait class so that we can dynamically wait for frames
            // Video Tutorial Here - http://courses.ultimateqa.com/courses/synchronization-techniques
            _wait = new WebDriverWait(_driver, TimeSpan.FromSeconds(6));
            
            //navigate Dave Haeffner's practice automation page
            _driver.Navigate().GoToUrl("http://the-internet.herokuapp.com/tinymce");
            
            //wait until a frame is present and then switch to it
            _wait.Until(ExpectedConditions.FrameToBeAvailableAndSwitchToIt(By.Id("mce_0_ifr")));

            //find the editor and get the text
            var editor = _driver.FindElement(By.Id("tinymce"));
            var startText = editor.Text;

            //clear the editor, type a string, get the text
            editor.Clear();
            editor.SendKeys("www.ultimateqa.com");
            var endText = editor.Text;

            //make sure that we actually typed in the text in the appropriate place
            Assert.AreNotEqual(endText, startText);
            //Don't forget to switch to the default content when you're done messing with the page
            _driver.SwitchTo().DefaultContent();
        }
    }
}