How Do I programatically select text in a webBrowser Control? c#

Here's the Problem: I want to enable the user of my program to search a webBrowser control for a given keyword (standard Ctrl+ F). I am havi开发者_如何学运维ng no problem finding the keyword in the document and highlighting all the instances using a span and the replace() function. I am having trouble getting the "find next" functionlity that I want to work. When the user clicks Find next I want the document to scroll to the next instance. If I could get a bounding box I can use the navigate function. I have this same functionality working in a rich text box using the following code

                //Select the found text
                this.richTextBox.Select(matches[currentMatch], text.Length);
                //Scroll to the found text
                this.richTextBox.ScrollToCaret();
                //Focus so the highlighting shows up
                this.richTextBox.Focus();

Can anyone provide a methodology to get this to work in a webBrowser?

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I implemented a search feature in a WinForms app that had an embedded Web browser control. It had a separate text box for entering a search string and a 'Find' button. If the search string had changed since the last search, a button click meant a regular find, if not, it meant 'find again'. Here is the button handler:

private IHTMLTxtRange m_lastRange;
private AxWebBrowser m_browser;

private void OnSearch(object sender, EventArgs e) {

    if (Body != null) {

        IHTMLTxtRange range = Body.createTextRange();

        if (! m_fTextIsNew) {

            m_lastRange.moveStart("word", 1);
            m_lastRange.setEndPoint("EndToEnd", range);
            range = m_lastRange;
        }

        if (range.findText(m_txtSearch.Text, 0, 0)) {

            try {
                range.select();

                m_lastRange = range;

                m_fTextIsNew = false;
            } catch (COMException) {

                // don't know what to do
            }
        }
    }
}

private DispHTMLDocument Document {
    get {
        try {
            if (m_browser.Document != null) {
                return (DispHTMLDocument) m_browser.Document;
            }
        } catch (InvalidCastException) {

            // nothing to do
        }

        return null;
    }
}

private DispHTMLBody Body {
    get {
        if ( (Document != null) && (Document.body != null) ) {
            return (DispHTMLBody) Document.body;
        } else {
            return null;
        }
    }
}

m_fTextIsNew is set to true in the TextChanged handler of the search box.

Hope this helps.

Edit: added Body and Document properties