Difference between webdriver.Dispose(), .Close() and .Quit()

This is a good question I have seen people use Close() when they shouldn’t. I looked in the source code for the Selenium Client & WebDriver C# Bindings and found the following.

1. webDriver.Close() – Close the browser window that the driver has focus of
2. webDriver.Quit() – Calls Dispose()
3. webDriver.Dispose() Closes all browser windows and safely ends the session

The code below will dispose the driver object, ends the session and closes all browsers opened during a test whether the test fails or passes.

public IWebDriver Driver;

[SetUp]
public void SetupTest()
{
    Driver = WebDriverFactory.GetDriver();
}

[TearDown]
public void TearDown()
{
    if (Driver != null)
      Driver.Quit();
}

In summary ensure that Quit() or Dispose() is called before exiting the program, and don’t use the Close() method unless you’re sure of what you’re doing.

Note
I found this question when try to figure out a related problem why my VM’s were running out of harddrive space. Turns out an exception was causing Quit() or Dispose() to not be called every run which then caused the appData folder to fill the hard drive. So we were using the Quit() method correctly but the code was unreachable. Summary make sure all code paths will clean up your unmanaged objects by using exception safe patterns or implement IDisposable

Also
In the case of RemoteDriver calling Quit() or Dispose() will also close the session on the Selenium Server. If the session isn’t closed the log files for that session remain in memory.