How to use WebBrowser control DocumentCompleted event in C#?

Question

Before starting writing this question, i was trying to solve following

// 1. navigate to page
// 2. wait until page is downloaded
// 3. read and write some d         


        

Answer 1

I have yet to find a working solution to this problem online. Hopefully this will make it to the top and save everyone the months of tweaking I spent trying to solve it, and the edge cases associated with it. I have fought over this issue over the years as Microsoft has changed the implementation/reliability of isBusy and document.readystate. With IE8, I had to resort to the following solution. It's similar to the question/answer from Margus with a few exceptions. My code will handle nested frames, javascript/ajax requests and meta-redirects. I have simplified the code for clarity sake, but I also use a timeout function (not included) to reset the webpage after if 5 minutes domAccess still equals false.

private void m_WebBrowser_BeforeNavigate(object pDisp, ref object URL, ref object Flags, ref object TargetFrameName, ref object PostData, ref object Headers, ref bool Cancel)
{
    //Javascript Events Trigger a Before Navigate Twice, but the first event 
    //will contain javascript: in the URL so we can ignore it.
    if (!URL.ToString().ToUpper().StartsWith("JAVASCRIPT:"))
    {
        //indicate the dom is not available
        this.domAccess = false;
        this.activeRequests.Add(URL);
    }
}

private void m_WebBrowser_DocumentComplete(object pDisp, ref object URL) 
{

    this.activeRequests.RemoveAt(0);

    //if pDisp Matches the main activex instance then we are done.
    if (pDisp.Equals((SHDocVw.WebBrowser)m_WebBrowser.ActiveXInstance)) 
    {
        //Top Window has finished rendering 
        //Since it will always render last, clear the active requests.
        //This solves Meta Redirects causing out of sync request counts
        this.activeRequests.Clear();
    }
    else if (m_WebBrowser.Document != null)
    {
        //Some iframe completed dom render
    }

    //Record the final complete URL for reference
    if (this.activeRequests.Count == 0)
    {
        //Finished downloading page - dom access ready
        this.domAccess = true;
    }
}