data binding - asp.net Dropdown list databinding in runtime -

 con = new sqlconnection(s);         con.open();         if (radiobuttonlist1.selectedindex == 0)         {             cmd = new sqlcommand("select [item] veg_items", con);             da = new sqldataadapter(cmd);             dataset ds = new dataset();             da.fill(ds, "[item]");             dropdownlist1.datasource = ds.tables[0];             dropdownlist1.databind();         }         else if (radiobuttonlist1.selectedindex == 1)         {             cmd = new sqlcommand("select [item] nonveg_items", con);             da = new sqldataadapter(cmd);             dataset ds = new dataset();             da.fill(ds, "[item]");             dropdownlist1.datasource = ds.tables[0];             dropdownlist1.databind();          }             con.close();     } 

i have items in table , need items displayed in dropdownlist once select value in radiobuttonlist. visualized items in ds.tables[0] line can't bind them dropdownlist.

  con.open();         if (radiobuttonlist1.selectedindex == 0)         {             cmd = new sqlcommand("select [item] [veg_items]", con);             sqldatareader dr = cmd.executereader();             list<object> lt = new list<object>();             if (dr.hasrows)             {                 while (dr.read())                 {                      lt.add(dr["item"].tostring());                 }             }             dropdownlist1.datasource = lt;             dropdownlist1.databind();         }         else if (radiobuttonlist1.selectedindex == 1)         {             cmd = new sqlcommand("select [item] [nonveg_items]", con);             sqldatareader dr = cmd.executereader();             list<object> lt = new list<object>();             if (dr.hasrows)             {                 while (dr.read())                 {                      lt.add(dr["item"].tostring());                 }             }             dropdownlist1.datasource = lt;             dropdownlist1.databind();   }   con.close();