Selenium C# 不等待

Question

I'm working on an ASP.NET MVC college project and some part of the project requires to automate the process of submitting a problem on codeforces.com the problem is that when selenium does not wait until the element is presented so I get an error :

OpenQA.Selenium.StaleElementReferenceException: 'stale element reference: element is not attached to the page document

and while debugging everything is working fine without any error. I have tried a lot of things to solve it but in the end all methods end with that error or something like that.

Some of the methods I used: * wait until * use dummy action to wait like Maximize and Minimize * System Sleep

And here is my code

using System;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using OpenQA.Selenium.Support.UI;
using OpenQA.Selenium.Support;
using NUnit.Framework;

namespace AutoCodeforces
{
    [TestClass]
    public class Automate
    {
        IWebDriver chromeDriver = new ChromeDriver();
        [TestMethod]
        public void OpenCodeforces()
        {


            string handle = "A4AJudge";
            string password = "A4A123456789";
            string ProblemID = "33A";
            string LangValue = "54";
            string code = @"#include <iostream> #include <algorithm> #include <string> #include <cstdio> #include <vector> using namespace std; int a[1000], i, n, m, j, l, k, ans; int main() { scanf(" + @"% d % d % d" + @", &n, &m, &k); for (i = 0; i < m; i++) a[i] = 1000001; for (i = 0; i < n; i++) { scanf(" + " % d % d" + ", &j, &l); j--; a[j] = min(a[j], l); } for (i = 0; i < m; i++) ans += a[i]; ans = min(ans, k); cout << ans << endl; return 0; }";

            chromeDriver.Navigate().GoToUrl("http://codeforces.com/enter");
            chromeDriver.Manage().Window.Maximize();
            chromeDriver.FindElement(By.Id("handleOrEmail")).SendKeys(handle);
            chromeDriver.FindElement(By.Id("password")).SendKeys(password);
            chromeDriver.FindElement(By.ClassName("submit")).Click();


            //WebDriverWait wait = new WebDriverWait(chromeDriver, TimeSpan.FromMinutes(1));

            //IWebElement element = wait.Until(driver => driver.FindElement(By.XPath("//a[@href='/problemset']")));

            chromeDriver.FindElement(By.XPath("//a[@href='/problemset']")).Click();

            //element = wait.Until(driver => driver.FindElement(By.XPath("//a[@href='/problemset/submit']")));
            chromeDriver.FindElement(By.XPath("//a[@href='/problemset/submit']")).Click();

            //element = wait.Until(driver => driver.FindElement(By.XPath("//input[@name='submittedProblemCode']")));
            chromeDriver.FindElement(By.XPath("//input[@name='submittedProblemCode']")).SendKeys(ProblemID);



            IWebElement selecElement = chromeDriver.FindElement(By.Name("programTypeId"));
            SelectElement language = new SelectElement(selecElement);
            language.SelectByValue(LangValue);

            chromeDriver.FindElement(By.Id("sourceCodeTextarea")).SendKeys(code);

            chromeDriver.FindElement(By.ClassName("submit")).Click();

            //chromeDriver.Close();
            //chromeDriver.Quit();
        }       
    }
}

Any help, please?

Answer 1

I don't think your wait is "explicit" enough here -- You'll want to invoke wait.Until on the ExpectedConditions class, not just on driver.FindElement() returning an element.

ExpectedConditions for C# specifically is contained in an external namespace now -- standard Selenium bindings have been deprecated. You will need the DotNetSeleniumExtras.WaitHelpers NuGet package for this to work. I will provide an alternative solution that does not require an additional dependency.

Using DotNetSeleniumExtras.WaitHelpers and ExpectedConditions :

WebDriverWait wait = new WebDriverWait(chromeDriver, TimeSpan.FromMinutes(1));

IWebElement element = wait.Until(SeleniumExtras.WaitHelpers.ExpectedConditions.ElementToBeClickable(chromeDriver.FindElement(By.XPath("//a[@href='/problemset']"))));

Without using any external dependencies, invoking IWebElement.IsDisplayed() attribute:

WebDriverWait wait = new WebDriverWait(chromeDriver, TimeSpan.FromMinutes(1));

var isDisplayed = wait.Until(chromeDriver => chromeDriver.FindElement(By.XPath("//a[@href='/problemset']")).Displayed);

chromeDriver.FindElement(By.XPath("//a[@href='/problemset']")).Click();