WebBrowserDocumentCompletedEventHandler Don't wait for Ajax Async to complete

Question

After reading Dianyang Wu article and this excellent post I managed to build a small .net app (almost a C&P from Wu source code) to automatize tests (let's call it protoTestApp). My final goal is to open a dozen small windows and in each simulate a different user interacting with a web app to stress it.

It works for some extend but after I logon on the web app (let's call it InternalTestSubject) it calls a external url (let's call it ExternalTestSubject) and injects it's content on a iFrame. This particular external url is another web app and it ill look up for the parent window to get some parameters. Opening ExternalTestSubject directly is not a option.

My problem is at my protoTestApp I want to also interact with that ExternalTestSubject (find a button by id, click it, etc) but at my CompletedEvent handler the iFrame is still empty.

The WebBrowser shows both web apps full loaded and working, so I suppose the handler is just not waiting for the iFrame content to load since it's done by a Ajax async call.

Any advice to acomplish it?

Answer 1

I can imagine the frame reports to be ready but it actually does not. For instance, the frame contains frames, you have no way to know whether all these frames are loaded by using DocumentCompleted event.

In short: Using a frame to load external stuff and do the testing is not a good approach. Even if you use a timer to check the loading status manually. But according to security considerations, you will have many problems to access the DOM.

I have two suggestions for you:

1. Create a WebBrowser instance and open external test subject into it. You will have a very good chance to know, whether document (and its frames) have been loaded completely. You still have the full control to access any elements of the WebBrowser or cookies or click elements or change elements.

2. Use 3rd tool such as Selenium as test driver.

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Update 1:

As the questioner does not want any 3rd tool, I'd suggest let the internal test subject query the loading completeness of the target frame periodically. Possible code can be check document.readyState == 'complete'.

So far as I know, as the external test subject is embedded as frame, due to security consideration, you might not able to access the DOM of the frame. In other words, you cannot do mouse clicks, etc., unless you change the security settings for the Webbrowser control first.

Answer 2

I think I explained this in the answer you linked (and in more details in another related answer). AJAX pages are non-determinustic, so there is no generic approach.

Use periodic asynchronous polling to watch the page's current HTML snapshot or DOM for changes, the linked post illustrates how to do that. You can poll the frame's content in the same way.