How to use ShouldRespectTimeout method of PuppeteerSharp.Tests.WaitTaskTests.FrameWaitForSelectorTests class

Either give your submit button an id property and use the #submit selector you previously tried:

<button id="submit" type="submit" class="btn btn-danger btn-lg btn-block">Login</button>

Or use form button[type=submit] as selector.

I found a solution: If the pages will be created in the same scope as their browser instance, then the pages will be created as expected, otherwise Task.Run() will be stuck due to NewPageAsync() method.

Bad behaviour:

Task[] Tasks = new Task[1];
Browser browser = await Puppeteer.LaunchAsync
(
    new LaunchOptions
    {
        Headless = true,
        ExecutablePath = "Chromium\\chrome.exe"
    }
);
for (int i = 0; i < Tasks.Length; i++)
{
    int ThreadNumber = i;
    Tasks[i] = Task.Run(async () =>
    {
       Page page = await browser.NewPageAsync(); //stucks
    });
}

Task.WaitAll(Tasks);

As expected:

Task[] Tasks = new Task[1];
for (int i = 0; i < Tasks.Length; i++)
{
    int ThreadNumber = i;
    Tasks[i] = Task.Run(async () =>
    {
       Browser browser = await Puppeteer.LaunchAsync
       (
           new LaunchOptions
           {
                Headless = true,
               ExecutablePath = "Chromium\\chrome.exe"
           }
       );
       Page page = await browser.NewPageAsync(); //creates as expected
    });
}

Task.WaitAll(Tasks);

Anyway this is not the best solution because I have to create browsers for async tasks rather than using one browser for all async tasks. Hope someone can explain that. Thanks everyone for helping!

Got it:
var localStorage = await page.EvaluateFunctionAsync<Dictionary<string, string>>("async () => Object.assign({}, window.localStorage)");

From the examples in the docs, it looks like you have to do this:

// select the tag first
var element = await _page.QuerySelectorAsync("h1 > strong > a");

// then get the attribute
var url = await element.EvaluateFunctionAsync<string>("e => e.getAttribute('href')");
// OR
var url = await _page.EvaluateFunctionAsync<string>("e => e.getAttribute('href')", element);
// OR
var url = await (await element.GetPropertyAsync("href")).JsonValueAsync<string>();

// OR all in one
var url = await _page.EvaluateExpressionAsync<string>($"document.querySelector({"'h1 > strong > a'"}).getAttribute('href')");

You gotta apply this to the value of a select option, of course. Probably 'value' instead of 'href' and the correct selector.

System.ValueTuple was added in .NET 4.7. Upgrading your project to 4.7 would be easiest.

If you can't, but your project is targetting a version 4.5+ but less than 4.7, then you can install the System.ValueTuple NuGet package. If you run into any trouble there, see this answer.

After struggling with the issue for several hours, we finally located the issue. It is not related with Puppeteer that works like a charm but rather with the way a private blob storage container handles authentication: as our request contained an Authorization HTTP Header with a bearer token required by our own app, this header was sent by Chromium while retrieving remote images from the blob container. Unfortunately Azure service tried to handle that token and rejected our request.

How did we identify that? By connecting a chrome debugger to the Chromium instance and by checking the logs. Indeed it is possible to launch Puppeteer with a remote debugging port.

You can wait for some selector that might tell you that the page is ready. e.g.:

await page.WaitForSelectorAsync(".someSelector");

The problem is how the CSSStyleDeclaration is serialized. If that´s how Chromium decides to serialize that object there is nothing we can do there.

But, we can try to solve that from javascript using EvaluateFunctionAsync.

foreach (var handle in elementHandles)
{
  var style = await page.EvaluateFunctionAsync<Dictionary<string, string>>(
    "e => Object.entries(e.style).filter(i => isNaN(i[0]) && i[1]).map(i => { return { [i[0]] : i[1]}}).reduce((acc, cur) => { return {...acc, ...cur}}, {})", handle);
  var output = style.ToString();
}

Let's take a look at the javascript expression

e=> //We send the HTML element instead of the style property
  Object.entries(e.style) //We get all the property/value pairs from the CSSStyleDeclaration object
    // We want to exclude number properties (like 0,1,2) and empty values
    .filter(i => isNaN(i[0]) && i[1]) 
    //We turn them into objects
    .map(i => { return { [i[0]] : i[1]}})
    //We merge them into one single object that will be returned to C#
    .reduce((acc, cur) => { return {...acc, ...cur}}, {})

So, after many tries and a lot of searched, I ended up switching to Selenium, which seems to have better documentation and a lot of examples here. This is the code, that worked for me:

string locator1 = "td:Contains(\'41818397111\')";
string locator2 = "td[id = \'InvoiceDetails\']";
IWebElement webElement = driver.FindElement(Selenium.WebDriver.Extensions.By.JQuerySelector(locator1).Parent().Find(locator2));
webElement.Click();