в 15:30, 26 мая 2010

2010-05-26T15:30:57Z

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2010-05-26T12:00:03Z

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== Convert.FromBase64String and view state encoding==



<source lang="csharp">
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="SimpleViewState" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
<asp:Button ID="Button1" OnClick="Button1_Click" runat="server" Text="Button" /></div>
</form>
</body>
</html>
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 SimpleViewState : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Label1.Text = "Hello World!";
}
protected void Button1_Click(object sender, EventArgs e)
{
string viewStateString = "/wEPDwUKLTE2MjY5MTY1NQ9kFgICAw9kFgICAQ8PFgIeBFRleHQFDEhlbGxvIFdvcmxkIWRkZPsbiNOyNAufEt7OvNIbVYcGWHqf";

byte[] stringBytes = Convert.FromBase64String(viewStateString);

string decodedViewState = System.Text.Encoding.ASCII.GetString(stringBytes);
Label1.Text = decodedViewState;
}
}</source>

== Save string variable to ViewState==



<source lang="csharp">
File: Default.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="PreserveMembers" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:TextBox ID="txtValue"
runat="server"
Height="160px"
TextMode="MultiLine"
Width="460px">This is a test</asp:TextBox><br />
<br />
<asp:Button ID="cmdSave"
runat="server"
OnClick="cmdSave_Click"
Text="Save Contents" />
<asp:Button ID="cmdLoad"
runat="server"
OnClick="cmdLoad_Click"
Text="Load Contents" /></div>
</form>
</body>
</html>

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 PreserveMembers : System.Web.UI.Page
{
private string contents;
protected void Page_Load(object sender, EventArgs e)
{
if (this.IsPostBack)
{
contents = (string)ViewState["contents"];
}
}
protected void Page_PreRender(Object sender, EventArgs e)
{
ViewState["contents"] = contents;
}
protected void cmdSave_Click(object sender, EventArgs e)
{
contents = txtValue.Text;
txtValue.Text = "";
}
protected void cmdLoad_Click(object sender, EventArgs e)
{
txtValue.Text = contents;
}
}</source>

== Track Your Viewstate==



<source lang="csharp">
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs"
Inherits="Default" Theme="Core35-Basic" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Track Your Viewstate</title>
</head>
<body>
<form id="form1" runat="server">
<div id="pageContent">
<asp:Button ID="Button1" runat="server" Text="Post back..." OnClick="Button1_Click" />
<br />
<br />
</div>
</form>
</body>
</html>
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.HtmlControls;

public partial class Default : System.Web.UI.Page
{
protected void Page_PreInit(object sender, EventArgs e)
{
this.TraceEnabled = true;
}
protected void Page_Init(object sender, EventArgs e)
{
if (!IsPostBack)
{
this.ViewState["MyData"] = "Hello, world";
}
Trace.Warn("[MyData] now contains", (string) ViewState["MyData"]);
}

protected void Page_Load(object sender, EventArgs e)
{
Trace.Warn("[MyData] now contains", (string)ViewState["MyData"]);
}
}</source>

== Use ViewState to create a simple counter (C#)==



<source lang="csharp">
File: Default.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="SimpleCounter" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Button ID="cmdIncrement"
runat="server"
OnClick="cmdIncrement_Click"
Text="Increment" /><br />
<br />
<asp:Label ID="lblCount" runat="server"></asp:Label> </div>
</form>
</body>
</html>

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();
}
}</source>

== Use ViewState to store random data==



<source lang="csharp">
<%@ Page Language="C#" AutoEventWireup="true"
CodeFile="Default.aspx.cs" Inherits="ViewStateChunking" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
Use View --> Source to see the view
state of this page.</div>
</form>
</body>
</html>
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 ViewStateChunking : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Random rnd = new Random();
byte[] buffer = new byte[1050];
rnd.NextBytes(buffer);
ViewState["Data"] = buffer;
}
}</source>

== Visualize the current Base64-encoded contents of the view state==



<source lang="csharp">
<%@ Page Language="C#" AutoEventWireup="true" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Try to Break Your Viewstate</title>
</head>
<script language="javascript">
function ShowViewState()
{
var buf = document.forms[0]["__VIEWSTATE"].value;
var o = document.forms[0]["ViewStateBox"];
o.value = buf;
}
function UpdateViewState()
{
var o = document.forms[0]["ViewStateBox"];
var viewstate = document.forms[0]["__VIEWSTATE"];
viewstate.value = o.value;
}
</script>
<body>
<form id="form1" runat="server">
<div id="pageContent">
<input onclick="ShowViewState()" type="button" value="Display View State" style="width:200px" />
<input onclick="UpdateViewState()" type="button" value="Update View State" style="width:200px" />

<h2>Here"s Your (Encoded) ViewState</h2>
<asp:TextBox id="ViewStateBox" runat="server" TextMode="MultiLine" Width="100%" Height="250px"></asp:TextBox>
<asp:Button id="Button1" runat="server" Text="Post Back..."></asp:Button>
</div>
</form>
</body>
</html></source>

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ASP.NET Tutorial/Page Lifecycle/ViewState - История изменений

в 15:30, 26 мая 2010

Admin: 1 версия