try this
private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
comboBox1.Items.Clear();
comboBox2.Items.Clear();
comboBox3.Items.Clear();
foreach (HtmlElement el in webBrowser1.Document.GetElementsByTagName("select"))
{
if (el.Id == "DDL1")
FillComboBox(el, comboBox1);
else if (el.Id == "DDL2")
FillComboBox(el, comboBox2);
else if (el.Id == "DDL3")
FillComboBox(el, comboBox3);
}
}
private void FillComboBox(HtmlElement el, ComboBox cbx)
{
bool selected = false;
string selectedText = "";
foreach (HtmlElement comboItem in el.Children)
cbx.Items.Add(comboItem.InnerText);
foreach (HtmlElement comboItem in el.Children)
{
selected = Convert.ToBoolean(comboItem.GetAttribute("Selected"));
if (selected)
{
selectedText = comboItem.InnerText;
break;
}
}
cbx.Text = selectedText;
}