Running a javascript function in an instance of InternetExplorer

Question

I'm using

SHDocVw.InternetExplorer ie = new SHDocVw.InternetExplorer()

to control/automate an instance of internet explorer. On certain pages I'd like to run a javascript function (init()). It seems the best way to do this is to use an HtmlDocument's InvokeScript method and I've been trying the following with no luck:

void ie_DocumentComplete(object pDisp, ref object URL)
{
  System.Windows.Forms.HtmlDocument doc = ie.Document;
  doc.InvokeScript("init");
}

Which fails because 'doc' is null. I can't seem to get a System.Windows.Forms.HtmlDocument from ie.Document. Besides trying to above, I've also tried:

System.Windows.Forms.HtmlDocument doc2 = (System.Windows.Forms.HtmlDocument)ie.Document;

and

System.Windows.Forms.HtmlDocument doc2 = ie.Document as System.Windows.Forms.HtmlDocument;

Any ideas how I can get this to work - or an even better way to run scripts on the page?

Thanks!!

EDIT:

Another way to run a javascript function appears to be:

SHDocVw.InternetExplorer ie = new SHDocVw.InternetExplorer()
mshtml.HTMLDocument doc = ie.Document;
mshtml.IHTMLWindow2 win = doc.parentWindow as mshtml.IHTMLWindow2;
win.execScript("init();", "javascript");

But the line

mshtml.IHTMLWindow2 win = doc.parentWindow as mshtml.IHTMLWindow2;

throws an error that it is an invalid cast (InvalidCastException) - even though IntelliSense (and msdn) say doc.parentWindow is a IHTMLWindow2. Any ideas? (Also I've made sure a page has been fully loaded before running that code)

Answer 1

The SHDocVw.InternetExplorer.Document is of type mshtmlHTMLDocumentClass, so you need to reference Microsoft.mshtml

mshtml.HTMLDocumentClass doc = (mshtml.HTMLDocumentClass)ie.Document;

The ie object also has to navigate somewhere for the document to have a value. such as

object test = new object();
ie.Navigate("c:\\tmp\\test1.html", ref test, ref test, ref test, ref test);

Total init:

SHDocVw.InternetExplorer ie = new SHDocVw.InternetExplorer();
object test = new object();
ie.Navigate("c:\\tmp\\test1.html", ref test, ref test, ref test, ref test);
mshtml.HTMLDocumentClass doc = (mshtml.HTMLDocumentClass)ie.Document;

Answer 2

The problem had to do with threading - I've wasted so much time with STA issues you'd think I'd learn by now :).

Anyhow I found a way to get the second bit of code I posted working and running javascript functions in the IE window! Here is the code:

this.Dispatcher.Invoke(DispatcherPriority.Normal, (Action)(() =>
                {

                        mshtml.HTMLDocument doc = ie.Document;

                        mshtml.IHTMLWindow2 win = doc.parentWindow as IHTMLWindow2;
                        win.execScript("init();", "javascript");


                }));

Hope it helps someone!