How to make TextBox look like a DropDownList in ASP.Net

YES It is POSSIBLE , use ajax control toolkit's combobox , like this :

 <asp:ComboBox  ID="comPosition"   runat="server" AppendDataBoundItems="True" AutoCompleteMode="Suggest" AutoPostBack="True" DataSourceID="rdCombo" DataTextField="cont_name" DataValueField="cont_id" MaxLength="0" style="display: inline;">
                   </asp:ComboBox>  
                       <asp:SqlDataSource ID="rdCombo" runat="server" ConnectionString="<%$ ConnectionStrings:ABCConnectionString %>"
    SelectCommand="SELECT * FROM [sd_m_country]"></asp:SqlDataSource>

don't forget to put this above the above coding :

 <asp:ToolkitScriptManager ID="ProfileScriptManger" EnablePageMethods="True" runat="server"></asp:ToolkitScriptManager>

Download AjaxControlToolKit from here

http://www.asp.net/ajaxlibrary/act.ashx