Make ajax combobox like searchable dropdown in c# Web form

Question

ds=sql.getds("select top 20 candidateid,name from candidates");

ComboBox1.DataTextField = "name";

ComboBox1.DataValueField = "candidateid";

ComboBox1.DataSource = ds.Tables[0];

ComboBox1.DataBind();

 

 

<asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server"></asp:ToolkitScriptManager>

<asp:ComboBox ID="ComboBox1" runat="server" DropDownStyle="DropDown" ></asp:ComboBox>

 

Data is showing in combobox, but not able to type text in combobox. to searc in dropdownlist.