Python Selenium：在预期的_条件下为子级重用找到的元素

在Selenium中，如何在

Wait

的预期条件下为子级重用找到的元素

html示例：

<p class="some">1<p>
<div class="content">
   <p class="other">2<p>
   <p class="some">3<p>
</div>

但这样的事情是行不通的：

from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

wait = WebDriverWait(driver, 5)
elem = wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'div.content')))
elem.wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'p.some')))

不幸的是，现在我每次都必须在等待中编写一个完整的选择器路径。不舒服。

根据API，建造商的文件如下：

class selenium.webdriver.support.wait.WebDriverWait(driver, timeout, poll_frequency=0.5, ignored_exceptions=None)
where-
    Constructor, takes a WebDriver instance and timeout in seconds.
    driver - Instance of WebDriver (IEDriverServer, GeckoDriver, ChromeDriver or RemoteWebDriver)

wait = WebDriverWait(driver, 5)
elem = wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'div.content')))

wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'p.some'))) # considering 'p.some' as unique.

wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'div.content p.some'))) # considering 'div.content p.some' as unique.

因此，当您声明WebDriverWait的实例时，需要将WebDriver实例作为参数传递。传递WebElement的实例可能会引发异常

现在，WebDriverWait通过您创建的WebDriverWait实例实现，如下所示：

class selenium.webdriver.support.wait.WebDriverWait(driver, timeout, poll_frequency=0.5, ignored_exceptions=None)
where-
    Constructor, takes a WebDriver instance and timeout in seconds.
    driver - Instance of WebDriver (IEDriverServer, GeckoDriver, ChromeDriver or RemoteWebDriver)

wait = WebDriverWait(driver, 5)
elem = wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'div.content')))

wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'p.some'))) # considering 'p.some' as unique.

wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'div.content p.some'))) # considering 'div.content p.some' as unique.

现在，如果您再次希望诱导等待某些其他元素，您可以重新使用以前的WebDriverWait实例，如下所示：

class selenium.webdriver.support.wait.WebDriverWait(driver, timeout, poll_frequency=0.5, ignored_exceptions=None)
where-
    Constructor, takes a WebDriver instance and timeout in seconds.
    driver - Instance of WebDriver (IEDriverServer, GeckoDriver, ChromeDriver or RemoteWebDriver)

wait = WebDriverWait(driver, 5)
elem = wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'div.content')))

wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'p.some'))) # considering 'p.some' as unique.

wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'div.content p.some'))) # considering 'div.content p.some' as unique.

否则，还必须传递父节点以构造唯一的CSS_选择器，如下所示：

class selenium.webdriver.support.wait.WebDriverWait(driver, timeout, poll_frequency=0.5, ignored_exceptions=None)
where-
    Constructor, takes a WebDriver instance and timeout in seconds.
    driver - Instance of WebDriver (IEDriverServer, GeckoDriver, ChromeDriver or RemoteWebDriver)

wait = WebDriverWait(driver, 5)
elem = wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'div.content')))

wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'p.some'))) # considering 'p.some' as unique.

wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'div.content p.some'))) # considering 'div.content p.some' as unique.

试试这个：

wait = WebDriverWait(driver, 5)
elem =  wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, 'div.content')))
psome = wait.until(lambda d:elem.find_element_by_css_selector('p.some'))

---

注意：我实际上没有在Python中尝试过它，但是我在C和Java中使用了很多类似的技术，所以除非我有一些小的语法错误，否则我很确定它应该可以工作。

你不能调用

wait

作为

elem

的实例方法。一种方法是将需要查找的所有元素存储在

page_object.py

中，然后将其作为模块导入，并在任何时候重用元素。您能编写示例吗？这是我的问题。但是我想重用在

wait

中找到的元素。没有太多细节，lambda就像一个内部函数。Wait.until反复调用此函数，直到它返回除nil以外的任何值并且不引发异常为止。事实上，所有预期的_条件方法都返回这样的函数。