方法的通用类型参数

Question

如何创建接受通用参数的方法？

好的，这是我正在研究的确切内容：

下面的2种方法仅By.Id或By.LinkText有所不同

    private IWebElement FindElementById(string id)
    {
        WebDriverWait wait = new WebDriverWait(_driver, TimeSpan.FromSeconds(40));
        IWebElement we = null;

        wait.Until<bool>(x =>
        {
            we = x.FindElement(By.Id(id));
            bool isFound = false;

            try
            {
                if (we != null)
                    isFound = true;
            }
            catch (StaleElementReferenceException)
            {
                we = x.FindElement(By.Id(id));
            }

            return isFound;
        });

        return we;
    }

    private IWebElement FindElementByLinkText(string id)
    {
        WebDriverWait wait = new WebDriverWait(_driver, TimeSpan.FromSeconds(40));
        IWebElement we = null;

        wait.Until<bool>(x =>
        {
            we = x.FindElement(By.LinkText(id));
            bool isFound = false;

            try
            {
                if (we != null)
                    isFound = true;
            }
            catch (StaleElementReferenceException)
            {
                we = x.FindElement(By.LinkText(id));
            }

            return isFound;
        });

        return we;
    }

Answer 1

由于Selenium By函数是静态成员函数，符合Func<string, By>的类型签名，因此您可以轻松地修改代码，如下所示：

private IWebElement FindElementById(string id)
{
    return FindElementBy(By.Id, id);
}

private IWebElement FindElementByLinkText(string linkText)
{
    return FindElementBy(By.LinkText, linkText);
}

private IWebElement FindElementBy(Func<string, By> finder, string argument)
{
    WebDriverWait wait = new WebDriverWait(_driver, TimeSpan.FromSeconds(40));
    IWebElement we = null;

    wait.Until<bool>(x =>
    {
        we = x.FindElement(finder(argument));
        bool isFound = false;

        try
        {
            if (we != null)
                isFound = true;
        }
        catch (StaleElementReferenceException)
        {
            we = x.FindElement(finder(argument));
        }

        return isFound;
    });

    return we;
}