Question

I am trying to display HTML files (containing local images) in a WebBrowser control. User can select the file using an OpenFileDialog, after which it is displayed in the control.

But I have these problems I am struggling to solve:

1. Since I’ve added the control to my Form, it’s been loading really slowly. It takes almost 10s for the form to instantiate.

2. WebBrowser.Navigate only works the first time. When I try to load the second file, nothing happens. I have tried calling Refresh, Update, OpenNew, opening about:blank between two files, but I just don’t have a clue how to do it properly. Only the initially opened file remains shown, no exceptions or warnings ever pop up when I try to navigate to a different page.

Am I doing something wrong? For example, Lutz Roeder’s Writer starts instantly and loads subsequent files without problems, but it uses lots of interop (and is editable), so I am trying to avoid all that stuff.

Answer 1

The way I have been loading local .html files into a WebBrowser is like so:

OpenFileDialog ofd = new OpenFileDialog();
// Do filtering here
if (ofd.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
    webBrowser1.DocumentText = System.IO.File.ReadAllText(ofd.FileName);
}

It can load files one after another with no problems. If you are trying to load a big html file when the form is initializing or is opening this could explain the 10 second loading time. My form loaded almost instantly when it had a WebBrowser control on it.

Hope this helps!

Edit: Try setting the stream of the WebBrowser:

System.IO.Stream s = System.IO.File.OpenRead(ofd.FileName);
webBrowser1.DocumentStream = s;