Extend a non-static class with a protected constructor

Question

I'm trying to extend Selenium's By class found here.

public static class SeleniumExtensions
{
  public static By Text(this By by, string textToFind)
  {
    return By.XPath("");
  }
}

But I can't find my extension on the By class when I do the above.

Do you have a `using` statement containing the namespace that `SeleniumExtensions` is defined in? — canton7, Mar 04 '20 at 11:23
driver.IsVisible(By.Text("Sales")); gives me 'By does not contain a definition for Text' — , Mar 04 '20 at 11:27
Right. Extension methods work on *instances* of the type. So you could do `By by = ...; by.Text(...)`. But you can't add static methods to the `By` class — canton7, Mar 04 '20 at 11:30

score 0 · Answer 1 · answered Mar 04 '20 at 11:29

0

You need to call it on an instance of the By class, not on the By class itself. For example:

By by = ...;
by.Text("Sales");

answered Mar 04 '20 at 11:29

Ricardo Peres

I can't create an instance because the constructor is marked as protected. So I'm guessing what I'm trying to do is not possible? – Mar 04 '20 at 11:30
Are not subclasses of By? If not, then, yes, it is not possible, but I can't believe that there aren't. The extension method will apply to any subclasses, as they are By themselves. – Ricardo Peres Mar 04 '20 at 11:31
@marceli You can create an instance e.g. by calling `By.XPath(...)`. But that probably isn't what you *want* here – canton7 Mar 04 '20 at 11:31

1 Answers1