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Ch??ng 5

Application, Server
và Session

M?c tiêu
? T?p tin Global.asax

? Các s? ki?n trong Global.asax

? S? d?ng ??i t??ng Application

? S? d?ng ??i t??ng Server

? S? d?ng ??i t??ng Session

T?p Global.asax

L?u tr? trong th? m?c g?c c?a ?ng d?ng

??nh ngh?a ph?m vi c?a ?ng d?ng

Kh?i t?o các bi?n m?c application hay session

N?i k?t c? s? d? li?u

G?i cookie

Các s? ki?n trong Global.asax
S? ki?n M? t?

Application_Start Phát sinh lúc trang asp.net trong ?ng d?ng
???c g?i

Application_End Phát sinh lúc session cu?i cùng c?a ?ng d?ng
k?t thúc hay ?ng d?ng d?ng s? d?ng Internet
Services Manger snap-in.

Application_Begin Phát sinh lúc m?i l?n trang b?t ??u yêu
Request c?u( trang ???c n?p hay refresh).

Events in Global.asax
Contd…
S? ki?n M? t?

Application_EndR Phát sinh m?i l?n m?t yêu c?u c?a trang k?t
equest thúc

Session_Start Phát sinh m?i l?n session b?t ??u.

Session_End Phát sinh m?i l?n session k?t thúc.

Global.asax Ví d?
Global.asax

<script language="C#" runat="server">
protected void Application_Start(Object sender,
EventArgs e)
{
}

protected void Session_Start(Object sender,
EventArgs e)
{
Response.Write( "Session Started <br>");
}

Global.asax Example
protected void Application_BeginRequest(Object
sender, EventArgs e)
{
Response.Write("<h1>Application
Begins</h1>");
Response.Write ("Application request begins
<br>");
}
protected void Application_EndRequest(Object
sender, EventArgs e)
{
Response.Write ("Application request ends
<br>");
}

Global.asax Ví d?
protected void Session_End(Object sender, EventArgs
e)
{
Response.Write("Session ended");
}
protected void Application_End (Object sender,
EventArgs e)
{
}
</script>

Test Global.asax
<html>
<title>Testing Global</title>
void Page_Load(Object sender, EventArgs e)
{
Response.Write ("Page Load event <br>");
}
</script>
</html>

??i t??ng Application
Bi?u di?n m?t th? hi?n c?a m?t ?ng d?ng ASP.NET.

Object[varName] Application Level
Session Level

Application ["greeting"] = "Welcome to our sites";

??i t??ng Application Ví d?
void Application_Start(Object sender, EventArgs E)
{
Application ["sessioncount"] = 0;
}

<HTML>
<script Language ="C#" runat ="server" Debug = "true">
void Page_Load(Object Src, EventArgs E)
{
Response.Write (“Your visitor number is “ +
Application ["sessioncount"]);
}
</script>
<form runat= "server" >
</form>
</HTML>

??i t??ng Application Ví d?
void Session_Start(Object sender, EventArgs e)
{

Application["sessioncount"]=(Int32)Application["sessionco
unt"] + 1;
}
<html>
<script Language ="C#" runat ="server" Debug = "true">
{
Response.Write ("Your visitor number is :" + Application
["sessioncount"]);
}
</script>
<form runat= "server" > </form>
</html>

??i t??ng Application k?t xu?t

Output after
Output Initially
refreshing

Output after reopening
the browser

Ki?m soát truy xu?t
? Bi?n ?ng d?ng có th? ???c truy xu?t và c?p nh?t b?i
t?t c? các trang trong ?ng d?ng ASP.NET

? B?i vì bi?n ch? duy trì m?t giá tr?, nên n?u ng??i dùng
thay ??i m?t giá tr? c?a bi?n nó s? thay ??i ??n t?t c?
ng??i dùng trong ?ng d?ng
? ?? ??m b?o các bi?n m?c ?ng d?ng kh?ng ???c
c?p nh?t m?t các ??ng th?i, ??i t??ng Application s?
d?ng ph??ng th?c Lock() và UnLock().

CoKi?m soát truy xu?t
Application.Lock();
//…code to change the value of the application
variables
……………
…………
Application.UnLock();

Ph??ng th?c Lock khóa t?t c? các bi?n trong kh?i m?

??m b?o ch? m?t ng??i dùng hi?n t?i có ?i?u khi?n
qua trang.
Khi ph??ng th?c UnLock ???c g?i, ng??i dùng hi?n t?i
m?t ki?m soát

M?ng
? M?ng m?c ?ng d?ng có th? chia x? nhóm các th?ng tin chung qua
toàn b? ?ng d?ng
? Th?ng th??ng các m?ng m?c ?ng d?ng s? d?ng th?ng tin t?nh.
? Khi s? d?ng m?ng trong ??i t??ng ?ng d?ng các ph?n t? trong m?ng
kh?ng nên thay ??i tr?c ti?p

String [] job = new String [4];
job[0]= "Faculty";
job[1]= "Programmer";
job[2]= "Salesman";
job[3]= "Manager";
Application ["j"] = job;

Array.aspx
<HTML>
<script Language ="C#" runat ="server" >
{ int i = 0; String[] k;
k = (String[])Application["j"];
for (i = 0; i<k.Length;i++)
{
Response.Write(k[i] + "<br>");
}
}
</script>
</HTML>

??i t??ng Server
Cho phép web server có th? ???c ki?m soát và ho?t
??ng nh? là m?t giao ti?p v?i HTTP service

Server.property | method
Thu?c tính M? t?

ScriptTimeo Ch? ra kho?ng th?i gian m?t script ???c ch?y trên
ut server tr??c khi nó k?t thúc
MachineName Dùng ?? l?y tên máy c?a server

Execute and Transfer
HTMLEncode
URLEncode
MapPath

Ph??ng th?c Execute
Ph??ng th?c Execute() dùng ?? truy?n th?c thi t? trang hi?n t?i
??n m?t trang khác, và tr? l?i th?c thi ??n trang hi?n t?i

<%@ Page Debug ="true"%><html>
void clicked (Object Src, EventArgs E)
{Server.Execute (“Array.aspx");}
</script>
<form runat ="server">
<asp:button id = "btnClick" onclick = "clicked"
Text =" Click me to transfer execution" runat =
"server" />
</form>
</html>

Ph??ng th?c Transfer
Ph??ng th?c này dùng ?? truy?n toàn b? th?c thi ??n m?t trang nào ?ó
Khác v?i ph??ng th?c Execute(), ki?m soát b? m?t t? trang g?i ph??ng
th?c th?c thi

Syntax:
Server.Transfer (“Array.aspx");

Ph??ng th?c HTMLEncode
? HtmlEncode() dùng ?? m? hóa m?t chu?i
HTML nào ?ó.
? Trong tr??ng h?p kh?ng g?i ph??ng th?c
HtmlEncode() method is not specified, <H1>
???c trình hi?u là m?t th? HTML, và th? ???c
hi?n th? theo.
? Cú pháp ph??ng th?c HtmlEncode() :

Server.HTMLEncode (string)

Ví d? HTMLEncode
<%@ Page Debug ="true"%>
<html>
<title>HtmlEncode</title>
void Page_Load (Object Src, EventArgs E)
{
Response.Write (Server.HtmlEncode("<H1> is an
example of a Heading tag</H1>"));
}
</script>
<form runat ="server"></form>
</html>

HTMLEncode k?t xu?t
Response.Write( Server.HtmlEncode("<H1> is an
example of a Heading tag</H1>"));

Response.Write("<br><H1> is an
example of a Heading tag</H1>");

Ph??ng th?c URLEncode
? M?t URL có th? dùng ?? g?i d? li?u t? client ??n m?t
t?p tin trên server
? N?u d? li?u kh?ng ph?i kí t? alphanumeric nó c?n ???c
m? hóa tr??c khi g?i ??n server.
? Cú pháp:

Server.URLEncode(string);

URLEncode Ví d?
<html>
<title>UrlEncode</title>
void Page_Load(Object Src, EventArgs e)
{
Response.Write(Server.UrlEncode ("http://
URLEncode.aspx"));
}
</script>
<form runat ="server"></form>
</html>

<html>
void Meclicked(Object Src, EventArgs e)
{
string MyMessage = Server.UrlEncode ("This is my
message to you");
Response.Redirect ("Array.aspx?MessageTB=" +
MyMessage);
}
</script>
<asp:button id = "btnClick" onclick = "Meclicked"
Text = "Click me to send messages" runat = "server"/>
</form>
</html>

Khi m? ???c th?c thi, trang ‘Array.aspx’ ???c g?i t? Web Server ?? x? l?
th?ng tin ???c g?i trong URL.
T?p tin ‘Array.aspx’ có th? l?y d? li?u trong tr??ng MyMessage.
K?t xu?t

Ph??ng th?c MapPath
? Dùng b?i server ?? ánh x? ???ng d?n ??n
th?ng tin trên server
? Ph??ng th?c này là m?t giao ti?p gi?a th?
m?c ?o và th? m?c v?t l? trên Web Server
? Cú pháp:

Server.MapPath (path)

MapPath Ví d? 1
<html>
{
Response.Write (Server.MapPath("/Array.aspx"));
}
</script>
</form>
</html>

MapPath Ví d? 2
<html>
<title>MapPath-ServerVariables </title>
{
Response.Write (Server.MapPath
(Request.ServerVariables.Get ("PATH_INFO")));
}
</script>
<form runat ="server"> </form>
</html>

??i t??ng Session
? Dùng ?? l?u tr? th?ng tin v? ng??i dùng
? Th?ng tin này ???c duy trì trong su?t phiên làm vi?c c?a ng??i dùng
? Bi?n l?u tr? trong ??i t??ng Session kh?ng b? lo?i b? khi trình duy?t ng??i
dùng chuy?n t? trang này ??n trang khác bên trong cùng m?t ?ng d?ng
? ??i t??ng b? h?y khi ng??i dùng k?t thúc session hay h?t h?n th?i gian t?n t?i
cho m?t session

Ch?a th?ng tin ng??i dùng ??c bi?t

Theo d?i và giám sát th?ng tin ng??i dùng trong
m?t session
H?y ??i t??ng sau khi session h?t h?n

S? d?ng Variable
? M?t bi?n session khác bi?n ?ng d?ng
? Bi?n session ch? dành cho m?t ng??i dùng nào ?ó bên
trong m?t session
? Bi?n ?ng d?ng có th? truy xu?t hay thay ??i b?i các
ng??i dùng khác trong ?ng d?ng
? Bi?n session ch? ???c truy xu?t qua phiên làm vi?c c?a
ng??i dùng ?ó.

S? d?ng Variable – ví d? 1
<html>
<title>Session Variable</title>
void Page_Load(Object Sender, EventArgs e)
{
Response.Write("<u><b><center>Logon
authentication using Session
variables</center></b></u><br><br>");
}
void WritingSesVar(Object Sender, EventArgs e)
{
Session["Name"] = txtUserName.Text;
Session["Password"] = txtPassword.Value;
lblMessage1.Text = "Session variables
stored";

lblMessage2.Text = "";
}

void ReadingSesVar(Object Sender, EventArgs e)
{
lblMessage1.Text = "The value of name is " + Session
["Name"];
lblMessage2.Text = "The value of password is " +
Session ["Password"];
}
void Clear(Object Sender, EventArgs e)
{
}

</script>
<form runat="server">
User name :
<asp:TextBox id = "txtUserName" runat="server" />
<br><br>
Password :
<input id="txtPassword" type="password" runat="server">
<br><br>
<asp:button id="btnStoreVar" text="Store in Session
Variables" onclick="WritingSesVar" runat="server" />
<asp:button id="btnReadVar" text="Read Session
Variables" onclick="ReadingSesVar" runat="server" />
<asp:button id="btnClearLabel" text="Clear Label"
onclick="Clear" runat="server"/>

S? d?ng Variable – K?t xu?t
<br><br>
<asp:Label id = "lblMessage1" runat="server" />
<br><br>
<asp:Label id = "lblMessage2" runat="server" />
<br><br>
</form>
</html>

Thay ??i bi?n
? Giá tr? trong m?t bi?n session c?ng có th? ???c ??c t? các trang web khác

SessionVariable1.aspx

<html>
void Page_Load(Object Sender, EventArgs e)
{
Response.Write("<u><b><center>Logon authentication
using Session variables</center></b></u><br><br>");
}

SessionVariable1.aspx …
void WritingSesVar(Object Sender, EventArgs e)
{
Session["Name"] = txtUserName.Text;
Session["Password"] = txtPassword.Value;
lblMessage.Text = "Session variables stored";
}
void ReadingSesVar(Object Sender, EventArgs E)
{
Response.Redirect("SessionVariableRedirected.aspx");
}
</script>
User name :
<asp:TextBox id = "txtUserName" runat="server" /><br><br>
Password :
<input id="txtPassword" type="password" runat="server"><br><br>

SessionVariableRedirected.as
px
<asp:button id="btnStoreVar" text="Store in Session
Variables" onclick="WritingSesVar" runat="server" />
<asp:button id="btnReadVar" text="Read Session
Variables" onclick="ReadingSesVar" runat="server" />
<br><br>
<asp:Label id = "lblMessage" runat="server"
/><br><br>
</form>
</html>

SessionVariableRedirected.asp
x
<html>
<title>Redirected Page</title>

x
void Page_Load(Object Sender, EventArgs E)
{
Response.Write("<u><b><center>Logon authentication
using Session variables</center></b></u><br><br>");
lblMessage1.Text = "User Name : " +
(String)Session ["Name"];
lblMessage2.Text = "Password : " +
(String)Session["Password"];
}
</script>
<asp:Label id = "lblMessage1" runat="server" /> <br><br>
<asp:Label id = "lblMessage2" runat="server" /> <br><br>
</form>
</html>

x k?t xu?t

S? ki?n và thu?c tính c?a
Session

Session.collection | property | method

Thu?c tính M? t?
SessionID Xác ??nh tính duy nh?t c?a ng??i dùng
TimeOut User timeout
LCID Local identifier
IsNewSession Tr? v? true n?u session ???c t?o trong yêu c?u
hi?n t?i
Item Tên c?a giá tr? Session
Count S? các m?c trong t?p h?p tr?ng thái session

Session ví d?
<HTML>
{
Response.Write("<b><u><center>Use of
LCID</b></u></center><br>");
DateTime dt;
dt = DateTime.Now;
int due = 500;
Response.Write ("Today's date is : " +
dt.ToShortDateString() + "<br><br>");
Response.Write ("The total amount due is " + due.ToString
("C") ); }
</script>
</HTML>

Session ví d?
<HTML>
<title>Session – LCID French</title>
{
Response.Write("<b><u><center>Change of LCID </b>
</u> </center> <br>");
Session.LCID =0x040C;
DateTime dt;
dt = DateTime.Now;
int due = 500;
Response.Write ("Today's date is : " +
dt.ToShortDateString() + "<br>");

Session k?t xu?t
Response.Write ("The total amount due is : " +
due.ToString ("C")) ;
}
</script>
</HTML>

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