c# - WebDriver 和 C# - NoSuchElement 异常

Question

我有以下代码用于从给定列表中选择一个选项，它通常有效，但有时它会失败并在第二个 if 上出现 NoSuchElement 异常。我的印象是，如果它找不到元素，它就会再次返回循环。我相信解释很简单......谁能启发我？

    public static void selectFromList(String vList, String vText, IWebDriver driver)
    {
        for (int sec = 0; ; sec++)
        {
            System.Threading.Thread.Sleep(2500);
            if (sec >= 10) Debug.Fail("timeout : " + vList);
            if (driver.FindElement(By.Id(ConfigurationManager.AppSettings[vList])).Displayed) break;
        }
        new SelectElement(driver.FindElement(By.Id(ConfigurationManager.AppSettings[vList]))).SelectByText(vText);
    }

Answer 1

与其 try catch 每个实例，不如创建一个帮助程序/扩展方法来为您处理。这里它返回元素，如果不存在则返回 null。然后你可以简单地为 .exists() 使用另一种扩展方法。

IWebElement element = driver.FindElmentSafe(By.Id("id"));

    /// <summary>
    /// Same as FindElement only returns null when not found instead of an exception.
    /// </summary>
    /// <param name="driver">current browser instance</param>
    /// <param name="by">The search string for finding element</param>
    /// <returns>Returns element or null if not found</returns>
    public static IWebElement FindElementSafe(this IWebDriver driver, By by)
    {
        try
        {
            return driver.FindElement(by);
        }
        catch (NoSuchElementException)
        {
            return null;
        }
    }

bool exists = element.Exists();

    /// <summary>
    /// Requires finding element by FindElementSafe(By).
    /// Returns T/F depending on if element is defined or null.
    /// </summary>
    /// <param name="element">Current element</param>
    /// <returns>Returns T/F depending on if element is defined or null.</returns>
    public static bool Exists(this IWebElement element)
    {
        if (element == null)
        { return false; }
        return true;
    }