ASP.NET.in.a.Nutshell.Second.Edition [Electronic resources] نسخه متنی

17.3 Collections Reference

The Response object in ASP.NET supports
only a single collection, the Cookies collection.

HttpCookieCollection = Response.Cookies

The Cookies collection returns an instance
of the HttpCookieCollection class containing all
cookies sent as a part of the current request. The
HttpCookieCollection class contains an instance of
the HttpCookie class for each cookie passed as
part of the client request. The properties of these HttpCookie
instances can be used to access information about the cookie(s). The
Cookies collection of the Response class supports
the following set of properties:

AllKeys

Returns a string array of all keys in the collection.

Count

Returns an integer count of the number of name/value pairs in the
collection.

Item (Index|Key)

Returns an instance of the collection class based on the index or
passed-in key. This is the default property, which is why calling:

Response.Cookies (KeyVal)

returns the HttpCookie instance corresponding to
KeyVal.

Keys

Returns a collection of the keys for the collection.

In addition, the HttpCookieCollection class
exposes the following methods:

CopyTo (Array, Index)

Copies the contents of the collection object to the provided
Array argument, starting at the provided
Index argument. Note that the array must
be dimensioned to a sufficient size to contain the collection before
calling CopyTo.

GetKey (Index)

Returns a string containing the key corresponding to the provided
Index argument.

As in classic ASP, the Cookies collection is still implemented as a
collection (in fact, the HttpCookieCollection
class inherits from the .NET
NameObjectCollectionBase class), but rather than a
collection of string keys and string values, the ASP.NET
implementation is a collection of string keys and objects (instances
of the HttpCookie class). Individual cookies are
retrieved into variables of type HttpCookie, providing access to the
cookies values through class properties.

Dictionary-style cookies (cookies with more than one value) are
accessible through the Values property of the
HttpCookie class, which returns a
NameValueCollection containing the cookie subkeys and values. You can
also set individual values by their key with the following syntax:

HttpCookie.Values("keyname") = "value"

Parameters

HttpCookieCollection

An Object variable of type HttpCookieCollection.

Example

The example creates a login cookie, sets the expiration of the cookie
for 30 minutes from the current time, and adds the cookie to the
Cookies collection.

Sub Page_Load( )
Dim myCookie As New HttpCookie("LoggedIn")
myCookie.Value = "True"
myCookie.Expires = DateTime.Now.AddMinutes(30)
Response.Cookies.Add(myCookie)
End Sub

Notes

Unlike classic ASP, the collections in ASP.NET are zero-based, so the
first element in any collection or array will be 0, not 1. This is
especially important to remember when retrieving values by their
index.