如何在定位元素之前等待框架加载？

Question

我正在尝试等待Selenium切换变化的帧，然后再等待另一个元素。即

var wait = new WebDriverWait(driver, 15);
wait.Until(ExpectedConditions.FrameToBeAvailableAndSwitchToIt(By.Id("frameA"));

var wait2 = new WebDriverWait(driver, 15);
// wait for element within frameA to exist
wait2.Until(ExpectedConditions.ElementExists(By.Id("elementA")));

如果我在Thread.Sleep(1000);第二次等待之前进行一次简单的操作，它的功能就很好，但是如果没有这样做，我会得到以下错误：

'unknown error: unhandled inspector error: {"code":-32000,"message":"Cannot find context with specified id"}
    enter code here

有没有更好的方法来等待框架上下文切换完成，然后再等待填充该框架中的元素？

Answer 1

There are a couple of things you need to consider :

The line of code to switch to the frame looks perfect which doesn't throws any error :

var wait = new WebDriverWait(driver, 15);
wait.Until(ExpectedConditions.FrameToBeAvailableAndSwitchToIt(By.Id("frameA"));

In the next line you have tried the ExpectedConditions method ElementExists. As per the API Docs ElementExists Method is defined as :

An expectation for checking that an element is present on the DOM of a page. This does not necessarily mean that the element is visible.

Selenium can't interact with elements until the element is visible. Hence you need to use the method ElementIsVisible as follows :

var wait2 = new WebDriverWait(driver, 15);
wait2.Until(ExpectedConditions.ElementIsVisible(By.Id("elementA")));

Here you can find a detailed discussion on Ways to deal with #document under iframe