c# - Index was out of range. Must be non-negative and less than the size of the collection.\r\nParameter name: index -
    i beginner selenium c# .. when trying below code , throwing exception:      index out of range. must non-negative , less size of collection.       parameter name: index    please me on this   class program { static void main(string[] args) {      iwebdriver driver = new chromedriver();     driver.url = @"file:///c:/users/user/documents/visual%20studio%202012/projects/learnselenium_xpath/learnselenium_xpath/testpage.html";     var radiobutton = driver.findelements(by.name("color"))[0]; -->exception     radiobutton.click(); }          the .findelements  not seem find element, causing [0]  fail.   you should check result of driver.findelements(by.name("color"))  before accessing it.