If I understand it right the new ACT ComboBox Control is Bound once to a given Datasource.
But the count of the records I want to bind is very large.
So I want to load the content of the ComboBox List via Ajax after the user typed in a few charachters.
So at page load the combobox list should be empty and if something is typed in the list is loaded with the typed text as search text.

I tried this:

<asp:ComboBox ID="cbxCompany" DropDownStyle="DropDownList" runat="server" AutoCompleteMode="Append" /> 

Protected Sub cbxCompany_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cbxCompany.TextChanged
    Dim dt As DataTable = GetCompanies(cbxCompany.Text)
    cbxCompany.DataSource = dt
    cbxCompany.DataTextField = "nameout"
    cbxCompany.DataValueField = "cid"
    cbxCompany.DataBind()
End Sub

GetCompanies is my method for getting data from the database, the parameters filters the select statement. But this doesn't work.

Is there a way to reload the combobox content per Ajax?