The Response Object ASP.NET Objects: Interacting with the Framework

295 An indication of whether the current request is over a secure HTTPS connection.

6.6.6 The Response Object

The Response object is an instance of the HttpResponse class defined in the System.Web namespace. This object provides information and services related to the response that results from the current web request. These are the commonly used properties of the Response object: BufferOutput An indication of whether output will be buffered while being generated. The type is Boolean. When this property is False , output is sent to the client as it is generated. When it is True its default value, output is buffered until it has been completely generated, then it is sent to the client. If a particular page request requires a lot of processing, but portions of the page become available throughout that processing, it is beneficial to set this property to False so that the client gets at least some output as soon as possible. On the other hand, the benefit to setting this property to True is that the output can be stopped or changed, or the page can be redirected, in the middle of page processing without sending spurious output to the client. Cache The caching policy of a web page. The type is HttpCachePolicy defined in the System.Web namespace. Caching is not discussed in this book. Charset The character set used in the output stream. The type is String. The default is utf-8 . ContentEncoding The character encoding used in the output stream. The type is Encoding defined in the System.Text namespace. The default is an instance of the UTF8Encoding class defined in the System.Text namespace. ContentType The MIME content type of the output stream. The type is String. The default is texthtml . Cookies A collection of HttpCookie objects representing cookies to be transmitted to the client browser. The type is HttpCookieCollection defined in the System.Web namespace. See the discussion of cookies later in this chapter under Sect ion 6.8 . Expires The number of minutes for which the client browser should cache the web page output. The type is Integer. The default is . ExpiresAbsolute The date and time until which the client browser should cache the web page output. The type is Date. The default is DateTime.MinValue . Status 296 The HTTP status text to be returned to the client browser. The type is String. The default is 200 OK . StatusCode The HTTP status code to be returned to the client browser. The type is Integer. The default is 200 . StatusDescription The HTTP status description to be returned to the client browser. The type is String. The default is OK . These are some commonly used methods of the HttpResponse class: Redirect Sends a redirect message to the client browser. Client browsers respond by requesting the web page specified in the redirect message. The syntax is: Public Sub RedirectByVal url As String The url parameter specifies the address of the new page to be requested. Write Writes a value directly to the output stream. This method is useful within script blocks that are embedded on the web page. There are versions of this method that write a single character, an array of characters, an object, and a string. The syntax for the version that writes a string is: Public Overloads Sub WriteByVal s As String

6.7 Discovering Browser Capabilities