How to use DomGetBoxModelRequest class of PuppeteerSharp.Messaging package

You don't need to call Dispose if you call CloseAsync. Dispose is just a fire and forget call to CloseAsync. See.

Try to use "innerText" except "textContent".

var strValueEst = await page.EvaluateFunctionAsync(
  "()=>document.querySelector('#path > path > nbPoints').innerText"
);

You should be able to do

await page.EvaluateExpressionAsync("window.scrollBy(0, window.innerHeight)");

You might not be able to access to https://storage.googleapis.com/chromium-browser-snapshots/Win_x64/674921/chrome-win.zip.
If you can't access to that URL, you can try to download a Chromium 77 (or greater) manually, and use the ExecutablePath property to set the Chromium app location.

You can use different browser instances for each logical instances. I mean instead of trying to set different proxy for each page/tab with different proxy just create new browser instance and set proxy via launch args.

If this solution doesn't fit your needs, check this question. There is library for NodeJS which give ability to use different proxy per each page/tab. You can check that library source code and implement same things inside your C# application.

That library is using very simple method. Instead of sending requests via puppeter's browser/page library send request via nodejs http tools. It can be done by using method page.setRequestInterception. So library intercept each request from page, after that gather data and send request via http tools. I used C# a long time ago. So maybe I am wrong, but you can try to use HttpWebRequest or something similar. After you get result you should use method request.respond and pass response results there. In this way you can put any kind of proxy inside your application. Check here code of library.

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!

This works for me:

var alertMessage = "";
//attach to page during entire page life-cycle (until closed).
//handles the case where an javscript alert comes up during login.
page.Dialog += new EventHandler<DialogEventArgs>(async (sender, args) =>
{
    alertMessage = args.Dialog.Message;
    await args.Dialog.Accept(); //this closes it..
    Log.Information("Popup squashed in Login(): {0}", alertMessage);
    Thread.Sleep(500);
});

Try adding the URL/Domain to Internet Download Manager's exception list. It will ignore the download request.

This code will load www.kayak.com with no images:

using (var browser = await Puppeteer.LaunchAsync(new LaunchOptions { Headless = false }))
using (var page = await browser.NewPageAsync())
{
    await page.SetRequestInterceptionAsync(true);

    // disable images to download
    page.Request += (sender, e) =>
    {
        if (e.Request.ResourceType == ResourceType.Image)
            e.Request.AbortAsync();
        else
            e.Request.ContinueAsync();
    };
    await page.GoToAsync("https://www.kayak.com");
    Console.ReadLine();
}