Create event handler for OnScroll for web browser control

Question

Has any one successfully trapped the event of mouse scroll in a web browerser component?

I have two web browser controls i would like to scroll at the same time.

Answer 1

I was able to get this working as follows. This example assumes that both web browser controls are navigating to the same Url. I am also syncing the horizontal scrollbar in addition to the vertical - this can be omitted if it is not required.

webBrowser1.DocumentCompleted
    += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);
webBrowser2.DocumentCompleted
    += new WebBrowserDocumentCompletedEventHandler(webBrowser2_DocumentCompleted);

NavigateToPage("www.google.com");

....

private void NavigateToPage(string url)
{
    webBrowser1.Navigate(url);
    webBrowser2.Navigate(url);
}

private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
    webBrowser1.Document.Window.AttachEventHandler("onscroll", OnScrollEventHandler1);
}

private void webBrowser2_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
    webBrowser2.Document.Window.AttachEventHandler("onscroll", OnScrollEventHandler2);
}

public void OnScrollEventHandler1(object sender, EventArgs e)
{           
    webBrowser2.Document.GetElementsByTagName("HTML")[0].ScrollTop
        = webBrowser1.Document.GetElementsByTagName("HTML")[0].ScrollTop;
    webBrowser2.Document.GetElementsByTagName("HTML")[0].ScrollLeft
        = webBrowser1.Document.GetElementsByTagName("HTML")[0].ScrollLeft;
}

public void OnScrollEventHandler2(object sender, EventArgs e)
{
    webBrowser1.Document.GetElementsByTagName("HTML")[0].ScrollTop
        = webBrowser2.Document.GetElementsByTagName("HTML")[0].ScrollTop;
    webBrowser1.Document.GetElementsByTagName("HTML")[0].ScrollLeft
        = webBrowser2.Document.GetElementsByTagName("HTML")[0].ScrollLeft;
} 

I note your comment in How to retrieve the scrollbar position of the webbrowser control in .NET, relating to this operation

webBrowser1.Document.GetElementsByTagName("HTML")[0].ScrollTop

not working. I can confirm that this definitely works on my machine, so if this code does not work on yours I can look into alternatives.

Answer 2

The real event name is "onscroll" not "OnScroll". MSDN:http://msdn.microsoft.com/en-us/library/ie/ms536966(v=vs.85).aspx

Following code is firing the method when event occured.

 private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            webBrowser1.Document.Window.AttachEventHandler("onscroll", OnScrollEventHandler);
        }

        public void OnScrollEventHandler(object sender, EventArgs e)
        {

        }