How to execute Compound class names using WebDriver

If you have a Compound class and you want to do something like this:
IWebElement elem = Browser.Driver.FindElement(By.ClassName("name1 name2 name 3"));

you will get an error like:
"Compound class names are not supported. Consider searching for one class name and filtering the results."

The solution:
Use CssSelector, and put "." in front of each name, like this:
IWebElement elem = Browser.Driver.FindElement(By.CssSelector(".name1.name2.name 3"));