c＃在WebBrowser控件的多个下拉列表中选择单个项目

Question

I've been searching for a solution for this problem, but have yet to find one that works. I have a webBrowser control. There is a multiple drop down list that is structured like this:

<select name="cars" multiple>
  <option value="volvo">Volvo</option>
  <option value="saab" SELECTED>Saab</option>
  <option value="opel">Opel</option>
  <option value="audi" SELECTED>Audi</option>
</select>

<p>Hold down the Ctrl (windows) / Command (Mac) button to select multiple options.</p>

There are already some options selected. I need to select one other option, such as "Volvo" The typical was to do this would be to hold the ctrl key and right click on the option. I was looking at the sendKeys class, but I'm not entirely sure I'm doing it right. Here is what I have tried:

foreach (HtmlElement item in webBrowser1.Document.GetElementsByTagName("option"))
{
    if (item.InnerText == "Volvo")
    {
        item.Focus();
        SendKeys.Send("^(+)");//sends ctrl-space
    }
}

It doesn't seem to give the item focus, so I'm not sure if the SendKeys is working or not.

I also tried this :

foreach (HtmlElement item in webBrowser1.Document.GetElementsByTagName("option"))
{
    if (item.InnerText == "Volvo")
    {
        item.SetAttribute("SELECTED", "");
    }
}

...but this does not seem to work either.
Any help is appreciated

Answer 1

Well, I'm embarrassed to say that the answer was surprisingly simple...

Apparently the SetAttribute method does not take an empty string as a second argument. This is the solution that worked:

foreach (HtmlElement item in webBrowser1.Document.GetElementsByTagName("option"))
{
    if (item.InnerText == "Volvo")
    {
        item.SetAttribute("SELECTED", "SELECTED");
    }
}