ASP.NET Tutorial/Cookie/Introduction — различия между версиями
Admin (обсуждение | вклад) м (1 версия) |
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(нет различий)
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Версия 15:30, 26 мая 2010
Create a persistent cookie.
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
void Page_Load()
{
int counter = 0;
if (Request.Cookies["counter"] != null)
counter = Int32.Parse(Request.Cookies["counter"].Value);
counter++;
Response.Cookies["counter"].Value = counter.ToString();
Response.Cookies["counter"].Expires = DateTime.Now.AddYears(2);
lblCounter.Text = counter.ToString();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>Set Persistent Cookie</title>
</head>
<body>
<form id="form1" runat="server">
<div>
You have visited this page
<asp:Label
id="lblCounter"
Runat="server" />
times!
</div>
</form>
</body>
</html>
Creating a new cookie.
Be warned that cookie names are case sensitive.
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void btnAdd_Click(object sender, EventArgs e)
{
Response.Cookies["message"].Value = txtCookieValue.Text;
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>Set Cookie</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Label
id="lblCookieValue"
Text="Cookie Value:"
AssociatedControlID="txtCookieValue"
Runat="server" />
<asp:TextBox
id="txtCookieValue"
Runat="server" />
<asp:Button
id="btnAdd"
Text="Add Value"
OnClick="btnAdd_Click"
Runat="server" />
</div>
</form>
</body>
</html>
Using Browser Cookies
When a web server creates a cookie, an additional HTTP header is sent to the browser when a page is served to the browser.
The HTTP header looks like this:
Set-Cookie: message=Hello
After a cookie has been created on a browser, whenever the browser requests a page from the same application in the future, the browser sends a header that looks like this:
Cookie: message=Hello
You can store only string values when using a cookie.
Two types of cookies: session cookies and persistent cookies.
A session cookie exists only in memory.
A persistent cookie can last for months or even years.
A persistent cookie is stored permanently by the user"s browser on the user"s computer.