Compound class names are not supported. Consider searching for one class name and filtering the results

原文地址：http://stackoverflow.com/questions/20361643/compound-class-names-are-not-supported-consider-searching-for-one-class-name-an

使用webdriver定位元素方法By.ClassName("btn-buy jq-productdetail-buy")时报的错误，查找到上述资料，说是因为中间的空格，它会识别为两个元素，而如果这样定位By.ClassName("btn-buy")，则会定位到classname包含btn-buy的所有元素的第一个，所以解决方案如下：

CssSelector (the best):

driver.FindElement(By.CssSelector(".bighead.crb")); // flexible, match "bighead small crb", "bighead crb", "crb bighead", etc.
driver.FindElement(By.CssSelector("[class*='bighead crb']")); // order matters, match class contains  "bighead crb"
driver.FindElement(By.CssSelector("[class='bighead crb']")); // match "bighead crb" strictly

XPath (the better):

driver.FindElement(By.XPath(".//*[contains(@class, 'bighead') and contains(@class, 'crb')]")); // flexible, match "bighead small crb", "bighead crb", "crb bighead", etc.
driver.FindElement(By.XPath(".//*[contains(@class, 'bighead crb')]")); // order matters, match class contains string "bighead crb" only
driver.FindElement(By.XPath(".//*[@class='bighead crb']")); // match class with string "bighead crb" strictly