using System.Data.SqlClient;

   string baglanti = "BURAYA SQL BAĞLANTI CÜMLENİZİ GİRİN"
   SqlDataSource ddl_datasource = new SqlDataSource(baglanti, "select * from uyeler");
   DropDownList1.DataTextField = "uye_adi";
   DropDownList1.DataValueField = "uye_id";
   DropDownList1.DataSource = ddl_datasource;
   DropDownList1.DataBind();
   ddl_datasource.Dispose();