Editable DropDownList field

Question

I want to make free text field but show some suggestions under it when dropdown arrow selected. Suggestions will be read from database they are not static How can I do this with asp ? My dropdown field is as follows:

<asp:DropDownList style="width:50%;" ID="ctlAramaKayitlari" runat="server" 
OnSelectedIndexChanged="ctlAramaKayitlari_SelectedIndexChanged" AutoPostBack="True" 
AppendDataBoundItems="True"></asp:DropDownList>

Answer 1

<ajaxtoolkit:combobox AutoCompleteMode="SuggestAppend" runat="server" 
ID="ctlAramaKayitlari" ></ajaxtoolkit:combobox>


private void BindAramaKayitlariCombo()
    {
        ctlAramaKayitlari.Clear();
        ctlAramaKayitlari.Items.Clear();
        ctlAramaKayitlari.DataBind();

        var _istKayitliAramaBE = new IstKayitliAramalarBE();
        _istKayitliAramaBE = BLLKayitliArama.KisiKayitliAramaByKisi(SecurityContext.CurrentUser.IdentityInfo.KAYITNO);
        if (_istKayitliAramaBE.ISTKAYITLIARAMA.Rows.Count > 0)
        {
            ctlAramaKayitlari.Items.Insert(0, new ListItem("--Kayıt Seçiniz--", "0"));
            ctlAramaKayitlari.DataSource = _istKayitliAramaBE.ISTKAYITLIARAMA;
            ctlAramaKayitlari.DataTextField = "ARAMAADI";
            ctlAramaKayitlari.DataValueField = "KAYITNO";
            ctlAramaKayitlari.DataBind();
        }
        else
        {
            ctlAramaKayitlari.Items.Insert(0, new ListItem("--Kayıtlı Aramanız Yoktur--", "0"));
        }
    }

solved