WinForms Webrowser Sync Scroll

Question

How do you sync scroll two winforms webrowser controls?

Meaning when you scroll one up and down, the other scrolls to the same spot in the underlying document?

Answer 1

I had this answer ahead of time but had no luck finding the answer via google, so I am posting here for posterity.

In the DocumentCompleted event for the browsers, add a handler to the webbrowser control's Window.Scroll event

webBrowserRight.Document.Window.Scroll += ScrollHandler;

I also set the titles here too (made distinguishing them easier when I needed to later)

webBrowserRight.Document.Title = "right";

Write the handler code - here I only needed to sync scroll vertically, but you could do the horizontal sync too.

private void ScrollHandler( object sender, EventArgs e )
{
    var scrolledBrowser = sender as HtmlWindow;
    if( scrolledBrowser == null ) return;

    // here you can see where I needed to distinguish the browser windows
    // none of the document, window etc properties matched the sender, so I
    // resorted to this hacky way
    WebBrowser otherBrowser = scrolledBrowser.Document.Title == "right" 
    ? webBrowserLeft 
    : webBrowserRight;
    int y = scrolledBrowser.Document.Body.ScrollRectangle.Top;
    otherBrowser.Document.Body.ScrollTop = y;
}