using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;      // Wymagane przez SqlDataAdapter.

public partial class _Default : System.Web.UI.Page
{
   protected void Page_Load(object sender, EventArgs e)
   {
      CreateGridView();
   }

   private void CreateGridView()
   {
      DataSet dsGrid;
      dsGrid = (DataSet)Cache["GridViewDataSet"];
      if (dsGrid == null)
      {
         dsGrid = GetDataSet();
         Cache["GridViewDataSet"] = dsGrid;
         lblMessage.Text = "Dane z bazy danych.";
      }
      else
      {
         lblMessage.Text = "Dane z bufora.";
      }

      gv.DataSource = dsGrid.Tables[0];
      gv.DataBind();
   }

   private DataSet GetDataSet()
   {
      // Poczenie z baz danych Northwind.
      string connectionString = "Data Source=MojSerwer;
         Initial Catalog=Northwind;Persist Security Info=True;
         User ID=uzytkownik;Password=sekret";

      // Pobranie rekordw z tabeli Customers.
      string commandString = "Select top 10 CustomerID, CompanyName,
         ContactName, City from Customers";

      // Tworzenie obiektu Command rda danych i obiektu DataSet.
      SqlDataAdapter dataAdapter = new SqlDataAdapter(commandString,
         connectionString);

      DataSet dsData = new DataSet();

      // Wypenienie danymi ustawionych obiektw.
      dataAdapter.Fill(dsData, "Customers");

      return dsData;
   }

   protected void btnClear_Click(object sender, EventArgs e)
   {
      Cache.Remove("GridViewDataSet");
      CreateGridView();
   }
}
