Detect WebBrowser complete page loading

Question

How can I detect when a System.Windows.Forms.WebBrowser control has completed loading?

I tried to use the Navigate and DocumentCompleted events but both of them were raised a few times during document loading!

Answer 1

I think the DocumentCompleted event will get fired for all child documents that are loaded as well (like JS and CSS, for example). You could look at the WebBrowserDocumentCompletedEventArgs in DocumentCompleted and check the Url property and compare that to the Url of the main page.

Answer 2

I did the following:

void BrowserDocumentCompleted(object sender,
        WebBrowserDocumentCompletedEventArgs e)
{
  if (e.Url.AbsolutePath != (sender as WebBrowser).Url.AbsolutePath)
    return; 

  //The page is finished loading 
}

The last page loaded tends to be the one navigated to, so this should work.

From here.

Answer 3

The following should work.

private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
    //Check if page is fully loaded or not
    if (this.webBrowser1.ReadyState != WebBrowserReadyState.Complete)
        return;
    else
        //Action to be taken on page loading completion
}

Answer 4

Note the url in DocumentCompleted can be different than navigating url due to server transfer or url normalization (e.g. you navigate to www.microsoft.com and got http://www.microsoft.com in documentcomplete)

In pages with no frames, this event fires one time after loading is complete. In pages with multiple frames, this event fires for each navigating frame (note navigation is supported inside a frame, for instance clicking a link in a frame could navigate the frame to another page). The highest level navigating frame, which may or may not be the top level browser, fires the final DocumentComplete event.

In native code you would compare the sender of the DocumentComplete event to determine if the event is the final event in the navigation or not. However in Windows Forms the sender parameter is not wrapped by WebBrowserDocumentCompletedEventArgs. You can either sink the native event to get the parameter's value, or check the readystate property of the browser or frame documents in the DocumentCompleted event handler to see if all frames are in the ready state.

There is a prolblem with the readystate method as if a download manager is present and the navigation is to a downloadable file, the navigation could be cancelled by the download manager and the readystate won't become complete.