把数据绑定到单个控件TextBox

Question

while(dr.Read()) 
         { 
            TextBox1.Text=dr["EquipID"].ToString(); 
            DropDownList1.DataSource=dr["EquipID"].ToString(); 
            DropDownList1.DataBind(); 
         } 
**************************************************************************.....
da.Fill(ds,"EquipType"); 
         System.Data.SqlClient.SqlDataReader dr; 
         SqlCommand cmd=new SqlCommand(select,conn); 
         dr=cmd.ExecuteReader(); 
         while(dr.Read()) 
         { 
            TextBox1.Text=dr["EquipID"].ToString(); 
         } 
         dr.Close(); 
         DropDownList1.DataSource=ds.Tables["EquipType"];
         DropDownList1.DataBind();          conn.Close();