.Net WebBrowser.DocumentText Isn't Changing!

Question

In my vb.net program, I am using a webbrowser to show the user an HTML preview. I was previously hitting a server to grab the HTML, then returning on an asynchronous thread

Answer 1

Try the following:

browser.Navigate("about:blank");
HtmlDocument doc = browser.Document;
doc.Write(String.Empty);
browser.DocumentText = _emailHTML;

I've found that the WebBrowser control usually needs to be initialized to about:blank anyway. The same needs to be done between navigates to different types of content (like text/xml to text/html) because the renderer is different (mshtml for text/html, something else for text/xml).

(via http://geekswithblogs.net/paulwhitblog/archive/2005/12/12/62961.aspx)

Answer 2

I found the best way to handle this, is as follows:

if (this.webBrowser1.Document == null)
{
    this.webBrowser1.DocumentText = htmlSource;
}
else
{
    this.webBrowser1.Document.OpenNew(true);
    this.webBrowser1.Document.Write(htmlSource);
}

Answer 3

Make sure that you do not cancel Navigating event of WebBrowser for about:blank page. WebBrowser navigates to about:blank before setting DocumentText. So if you want to handle links by yourself you need to create following handler of Navigating event:

private void webBrowser1_Navigating(object sender, WebBrowserNavigatingEventArgs e)
{
    if(e.Url.OriginalString.StartsWith("about:"))
    {
        return;
    }
    e.Cancel = true;
    // ...
}