get item from Html dropdown list

[dimitris.dimitri.73]

Dear forum ,
i am facing a problem when i try to populate my combobox item from a dropdownlist in html.
my code is the following which executes witount errors:

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Dim I As Integer = 0
        Dim NAME As String
        For I = 0 To 10
            NAME = WebBrowser1.Document.GetElementById("dropdownlistid").GetAttribute("value")
            MessageBox.Show(NAME)
            ComboBox1.Items.Add(NAME)

        Next




    End Sub

It doesnt display anything from the dropdownlist but it gives an error that index was out of range.