Webbrowser Find Previous (text)

I am trying to implement search routines: Find Next and Find Previous in Webbrowser. I know that there is Build-in Find dialog inside, but I do not want to use it. Instead I am trying hard to write my own routines, but I can not get through. Following code implements "Find next" nicely:

using mshtml;

....

private void toolStripButton5_Click(object sender, EventArgs e)
        {
            IHTMLDocument2 htmlDocument = WB.Document.DomDocument as IHTMLDocument2;
            IHTMLSelectionObject sel = (IHTMLSelectionObject)htmlDocument.selection;
            IHTMLTxtRange tr = (IHTMLTxtRange)sel.createRange() as IHTMLTxtRange;
            string s = toolStripTextBox1.Text;
            tr.collapse(false); 
            tr.findText(s, 1, 0); // positive value, should search forward, negative backward
            开发者_开发技巧tr.select();
        }

I am totaly helpless making "Find previous" routine. Can any genius forge it? (it will be probably very similar to that above).

Thanks very much

---

For "Find previous" routine use the same code with 2 modifications: 1) change argument of tr.collapse from false to true; 2) change the second parameter of tr.findText from 1 to -1.

So these line will be the following:

tr.collapse(true); // use true to move caret at the beginning of the current selection
tr.findText(s, -1, 0); // positive value, should search forward, negative backward

---

IHTMLTxtRange tmprange; private void Find(int Direction, bool Collapse) {

        IHTMLDocument2 htmlDocument = browser.Document.DomDocument as IHTMLDocument2;
        IHTMLSelectionObject sel = (IHTMLSelectionObject)htmlDocument.selection;
        IHTMLTxtRange tr = (IHTMLTxtRange)sel.createRange() as IHTMLTxtRange;
        string s = textBoxFindData.Text;
        if (tmprange == null)
        {
            tr.collapse(Collapse);
            tmprange = tr;
            tr.findText(s, Direction, 0); // positive value, should search forward, negative backward
            if (tr.text == null)
            {
                MessageBox.Show("Can not find string " + "[" + s + "]", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            tr.select();
        }
        else
        {
            tmprange.collapse(Collapse);
            tmprange.findText(s, Direction, 0); // positive value, should search forward, negative backward
            if (tmprange.text == null)
            {
                MessageBox.Show("Can not find string " + "[" + s + "]", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            tmprange.select();

        }
    }

    private void buttonPrevious_Click(object sender, EventArgs e)
    {
        Find(-1, true);
    }