Page Lifecycle ASP.Net Tutorial

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  4. Use ViewState to create a simple counter (C#)
File: Default.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="SimpleCounter" %>



    Untitled Page


    
    

                            runat="server" 
                    OnClick="cmdIncrement_Click" 
                    Text="Increment" />
        
         

    


File: Default.aspx.cs
using System;
using System.Data;
using System.Configuration;
using System.Collections;
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;
public partial class SimpleCounter : System.Web.UI.Page
{
  protected void cmdIncrement_Click(object sender, EventArgs e)
  {
        int counter;
        if (ViewState["Counter"] == null)
        {
            counter = 1;
        }
        else
        {
            counter = (int)ViewState["Counter"] + 1;
        }
        ViewState["Counter"] = counter;
        lblCount.Text = "Counter: " + counter.ToString();
  }
}