asp.net - DropDownList doesn't work with the codebehind C# -

so tried make dropdownlist. working when inside aspx file, doesn't work inside codebehind.

    <asp:panel id="pnlchannel" runat="server"> <asp:sqldatasource id="sdschannel" runat="server" connectionstring="<%$ connectionstrings:monitor_sql %>" selectcommand="select * table"></asp:sqldatasource> <asp:dropdownlist id="ddlchannel" runat="server"  datasourceid="sdschannel"  autopostback="true" datatextfield="kanal">  </asp:dropdownlist> </asp:panel> 

then tried codebehind in c#:

   public panel getdropdownlist() {     // create drop down list , data source     panel pnlchannel = new panel();     pnlchannel.id = "pnlchannel";     dropdownlist ddlchannel = new dropdownlist();     ddlchannel.id = "ddlchannel";     listitem limdefault = new listitem();     sqldatasource sdschannel = new sqldatasource();     sdschannel.id = "sdschannel";      // configure data source     sdschannel.connectionstring = configurationmanager.connectionstrings["monitor_sql"].connectionstring;     sdschannel.selectcommand = "select * table";       // configure drop down list     ddlchannel.datatextfield = "kanal";     ddlchannel.datavaluefield = "kanal";     ddlchannel.appenddatabounditems = true;     ddlchannel.datasourceid = "sdschannel";     ddlchannel.autopostback = true;        // configure default list item     limdefault.selected = true;     limdefault.text = "alle";     limdefault.value = "-1";      //add controls static panel in footer     ddlchannel.items.add(limdefault);     pnlchannel.controls.add(ddlchannel);     pnlchannel.controls.add(sdschannel);     return pnlchannel; } 

why isn't working? + not use both, want use 1 of these opinions

based on comment:

if if in codebehind there dropdownlist there nothing inside list

you never bound control data:

ddlchannel.databind();