Selenium webdriver window handles c# switchTo failed

Question

Here comes 2 windows pop out during the testing.

my code:

string BaseWindow = driver.CurrentWindowHandle;                 
ReadOnlyCollection

        

Answer 1

string NewWindowHandle = string.Empty;
ReadOnlyCollection windowHandles = driver.WindowHandles;
NewWindowHandle = windowHandles[windowHandles.Count - 1];
driver.SwitchTo().Window(NewWindowHandle);