ASP.NET Tutorial/Cookie/Introduction
Create a persistent cookie.
<source lang="csharp">
<%@ 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">
You have visited this page <asp:Label id="lblCounter" Runat="server" /> times!
</form>
</body> </html></source>
Creating a new cookie.
<source lang="csharp">
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">
<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" />
</form>
</body> </html></source>
Using Browser Cookies
<source lang="csharp">
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.</source>