如何在C＃中实现ExpectedConditions.AlertIsPresent

Question

using System;
using OpenQA.Selenium;

namespace MyApplication.Selenium.Tests.Source
{
    public sealed class MyExpectedConditions
    {

        private void ExpectedConditions()
        {
        }

        public static Func<IWebDriver, IAlert> AlertIsPresent()
        {
            return (driver) =>
            {
                try
                {
                    return driver.SwitchTo().Alert();
                }
                catch (NoAlertPresentException)
                {
                    return null;
                }
            };
        }

    }
}

You can use it like this:

new WebDriverWait(Driver, TimeSpan.FromSeconds(5)) { Message = "Waiting for alert to appear" }.Until(d => MyExpectedConditions.AlertIsPresent());
Driver.SwitchTo().Alert().Accept();

Answer 1

WebDriverWait will throw a WebDriverTimeoutException exception if alert is not found in the required wait period.

Use a try catch block around WebDriverWait to catch WebDriverTimeoutException .

I use an extension method like below:

public static IAlert WaitGetAlert(this IWebDriver driver, int waitTimeInSeconds = 5)
{
    IAlert alert = null;

    WebDriverWait wait = new WebDriverWait(driver, TimeSpan.FromSeconds(waitTimeInSeconds));

    try 
    {
        alert = wait.Until(d =>
            {
                try
                {
                    // Attempt to switch to an alert
                    return driver.SwitchTo().Alert();
                }
                catch (NoAlertPresentException)
                {
                    // Alert not present yet
                    return null;
                }
            });
    }
    catch (WebDriverTimeoutException) { alert = null; }

    return alert;
}

and use it like this:

var alert = this.Driver.WaitGetAlert();
if (alert != null)
{
    alert.Accept();
}