System.Exception: "IBrowserHost instance is null. Browser has likely not finished initializing or is in the process of disposing."

[Includephone]

Hello, i have a problem with adding cookies in Cookie Mananger. When i try to set cookie, i get System.Exception: "IBrowserHost instance is null. Browser has likely not finished initializing or is in the process of disposing."
The script works without errors when using Cef.GetGlobalCookieManager(), but I need to set the cookie to this particular browser instance

public partial class Form2 : Form
    {
        public Form2(Account account)
        {
            InitializeComponent();
            var browser = new ChromiumWebBrowser("www.google.com");
            RequestContextSettings requestContextSettings = new RequestContextSettings();
            requestContextSettings.PersistSessionCookies = false;
            requestContextSettings.PersistUserPreferences = false;
            requestContextSettings.CachePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "CefSharp\\Cache\\" + account.steamId);
            browser.RequestContext = new RequestContext(requestContextSettings);
            foreach (System.Net.Cookie cookieLine in account.cookie)
            {
                if (cookieLine.Name == "steamLoginSecure")
                {
                    var cookieMananger = browser.GetCookieManager();
                    Thread.Sleep(5000);
                    cookieMananger.SetCookie("https://steamcommunity.com/", new CefSharp.Cookie
                    {
                        Name = cookieLine.Name,
                        Value = cookieLine.Value,
                        Expires = cookieLine.Expires
                    });
                }
            }
            browser.Load("https://steamcommunity.com/");
            this.Controls.Add(browser);
        }
    }

[amaitland]

In future please use discussions to ask questions. This is not a bug.

https://github.com/cefsharp/CefSharp/discussions

Browser has likely not finished initializing

In your case the browser hasn't been initialized yet.

Wait for the browser to initialize before attempting to access the cookie manager.

https://github.com/cefsharp/CefSharp.MinimalExample/blob/master/CefSharp.MinimalExample.WinForms/BrowserForm.cs#L33

[mwpowellhtx]

Getting similar results. I second this issue nomination. Maybe we are doing something funny discussion worthy, but so far, looking like a bug. Happy to be incorrect in that. CEF is definitely claiming Initialized, however, the BrowserCore is definitely when that is raised, null.

As far as usage, I am starting from the minimal WPF example use case. So far I am creating the window with the CEF instance embedded, however, I am leaving it Visibility = Hidden for the time being, unless/until I need it. Maybe because it is hidden, i.e. not shown, some GC is happening that "should not", best guess. Behaviors are also involved almost verbatim from the minimal WPF samples, but I should not think those have any impact here, i.e. the hoverlink behaviors.

<Border BorderBrush="Gray" BorderThickness="0,1">
    <wpf:ChromiumWebBrowser x:Name="Browser" Address="..." Initialized="Wrapper_Browser_Initialized" />
</Border>

private void Wrapper_Browser_Initialized(object sender, EventArgs e)
{
    // sender is ChromiumWebBrowser, which BrowserCore is definitely null at the moment this is raised.
}

Under debugging watch:

[mwpowellhtx]

Trying a couple of things, still somewhat in learning phase, but things are becoming a bit clearer. It is very asynchronous, that much I can say. Doing a ton of async awaits, but they are at least evaluating, to a point, so that's a start, better than before.

The good news is, I can toggle visibility, with a subsequent await, so beyond that hurdle.

Wrapper.Visibility = Visibility.Visible;

// After turning the Window visible, must wait for rendering to complete, but it does (!) render.
await Wrapper.Browser.WaitForRenderIdleAsync();

// Selector waits are working it seems like, or the functional loading has not fully rendered...
await Wrapper.Browser.WaitForSelectorAsync("input[type = 'text', name = 'username']");
await Wrapper.Browser.WaitForSelectorAsync("input[type = 'password', name = 'password']");
await Wrapper.Browser.WaitForSelectorAsync("input[type = 'checkbox', name = 'rememberme']");
await Wrapper.Browser.WaitForSelectorAsync("button[type = 'submit', name = 'submitLogin']");

await using var context = await Wrapper.Browser.CreateDevToolsContextAsync();

var ctrlUsername = await context.QuerySelectorAsync<HtmlInputElement>("input[type = 'text', name = 'username']");
var ctrlPassword = await context.QuerySelectorAsync<HtmlInputElement>("input[type = 'password', name = 'password']");
// TODO: Feed me with View Model username and password.

var cbRememberMe = await context.QuerySelectorAsync<HtmlInputElement>("input[type = 'checkbox', name = 'rememberme']");
// Assuming from within the scope of the View Model.
await cbRememberMe.SetCheckedAsync(RememberMe);

// After having fed the controls, click.
await context.ClickAsync("button[type = 'submit', name = 'submitLogin']");

By comparison and/or contrast, from inside a Chrome dev tools console, I do have controls where I think I should have controls using the same selectors, everything else being equal.

[mwpowellhtx]

Getting an exception that query selector on the document is invalid on line:

var ctrlUsername = await context.QuerySelectorAsync<HtmlInputElement>("input[type = 'text', name = 'username']");

For whatever reason. It seems as though, either:

1. the Wrapper.Browser.WaitForSelectorAsync(...) is way too aggressive, not sure what it is watching for, the thing has not fully loaded; or
2. the subsequent context.QuerySelectorAsync<HtmlInputElement>("...") is unable to determine that the thing is the thing we thought it was, in this case, <input/>, for example; or
3. I cannot think of a third thing, outside the possibility that we need to properly align the selector with the generic, i.e. HtmlInputElement for <input/>, and so on.

Kind of at a loss, unless someone can offer some guidance, things to look for, getting this DOM puppeteering session on its feet.

[mwpowellhtx]

Did a minor adjustment still no luck. Here is the exception text:

await context.WaitForSelectorAsync("input[type='text', name='username']", new WaitForSelectorOptions { Timeout = 30000, Visible = true });

It fails immediately. Tried tick marks and full quotes in the selector string, neither case works. As I stated above, the same selector strings "just work" for purposes of the Chrome dev tools console. So not sure why they would not work here.

CefSharp.Dom.EvaluationFailedException: 'Evaluation failed: DOMException: Failed to execute 'querySelector' on 'Document': 'input[type="text", name="username"]' is not a valid selector.
    at predicate (eval at waitForPredicatePageFunction (:3:23), <anonymous>:7:30)
    at eval (eval at waitForPredicatePageFunction (:3:23), <anonymous>:23:17)
    at onRaf (__puppeteer_evaluation_script__:50:35)
    at pollRaf (__puppeteer_evaluation_script__:43:15)
    at waitForPredicatePageFunction (__puppeteer_evaluation_script__:8:22)'

[mwpowellhtx]

Next bit of a clue; the selector should work under Chrome console itself. If it is not working there, then it will not work through CEF. Troubleshooting that now.

[amaitland]

Failed to execute 'querySelector' on 'Document': 'input[type="text", name="username"]' is not a valid selector

That exception comes straight out of V8.

the selector should work under Chrome console itself. If it is not working there, then it will not work through CEF. Troubleshooting that now.

Use DevTools for debugging directly in the ChromiumWebBrowser instance. https://github.com/cefsharp/CefSharp/wiki/General-Usage#devtools

[mwpowellhtx]

For Pete's sake, VICTORY! 🎆 🔥

[mwpowellhtx]

That was it, the steps above, were more or less on point. And with a bit of DOM and query selector refinement. Got 'er working.

[mwpowellhtx]

For the issue itself, ensuring that the host Window is visible and has loaded fully, is the key for the Browser instance to also have been initialized and DOM available. Once that was the case, sorted out my Chrome selector query strings, which were also problematic. Once I got those sorted out, the rest flowed like magic seamlessly with the browser window.

[amaitland]

Wait for the browser to initialize before attempting to access the cookie manager.

https://github.com/cefsharp/CefSharp.MinimalExample/blob/master/CefSharp.MinimalExample.WinForms/BrowserForm.cs#L33

The WinForms and WPF implementations both have an IsBrowserInitializedChanged event that's fired when the browser is initialzied. (The link above is no off by one line, time goes on).

Getting similar results. I second this issue nomination. Maybe we are doing something funny discussion worthy, but so far, looking like a bug.

The code provided by the OP is incorrect (not a bug). Creating a browser instance then immediately attempting to access the cookie manager is never going to work. The same goes for almost every operation. The browser is created async and in the case of WinForms only when the controls Hwnd (handle) is created. (Remembering this discussion was originally about WinForms)

In WPF the browser is only created when it has a width/height. (CEF won't create a browser with size 0,0).

The OffScreen implementation is the only one that will attempt to create the browser when the ChromiumWebBrowser instance is created (again it's created async)

<wpf:ChromiumWebBrowser x:Name="Browser" Address="..." Initialized="Wrapper_Browser_Initialized" />

The WPF Initailzied even is not the same as the browser being initialized. The IsBrowserInitializedProperty dependency property can be used to track the browser state (in addition to the event mentioned above).

There's examples of waiting for the browser to initialize in https://github.com/cefsharp/CefSharp/wiki/General-Usage#devtools

• LoadingStateChanged event is useful in a lot of cases
• WaitForInitialLoadAsync is useful in cases where you wish to ensure the browser has finished loading the first page.

Plus the fact that the Initialized event is indeed being raised, at least as far as the CEF scaffold is concerned, we think it is initialized.

The WPF control has been initialized, different to Chromium being initialized. That's a standard WPF event (comes from FrameworkElement), it's not one that we can control.

Anyone can edit the WIKI, contributions are welcome and encouraged, if you'd like to see the documentation improved the please contribute!