The HttpResponse class is used to send information to the client's browser, including HTML content, HTML headers, and customized cookies. Its name derives from the fact that it is used to "respond" to an HTTP request.
The Redirect( ) method of the HttpResponse class provides the easiest way to programmatically send the user to another web page. You supply the name of the HTML or ASPX file as an argument (e.g., Response.Redirect ("newpage.aspx");). As long as the file is in the same directory as the current page, you don't need to provide a full URL (like http://www.mysite/myapplication/newpage.aspx), although you can use a relative path or fully-qualified URL. Other ways to transfer a user between pages in an ASP.NET program include the HttpServerUtility.Transfer( ) method and the System.Web.UI.WebControls.HyperLink web control.
The Cookies property of the HttpResponse class provides a reference to the application's HttpCookieCollection, which can send custom cookies to the client. The Cache property provides a reference to the application's HttpCachePolicy settings. Both classes are described separately. These properties, along with the Redirect( ) method, are the most commonly used members of HttpResponse.
In traditional ASP development, the Write( ) method was often used to append HTML to a web page (e.g., Reponse.Write "<h1>Hello World</h1>";). ASP.NET programs will rarely use this method because it is much easier to handle dynamic content by changing the properties of full-featured web controls on Web Forms. Similarly, the BinaryWrite( ) method, which allows you to write binary information into the HTTP text stream by supplying a byte array, or the WriteFile( ) method, which allows you to write the content from a named text file into the output stream, are rarely used.
The BufferOutput property is a Boolean value that determines whether or not the HTTP output is buffered. It is sent to the client only when it is fully rendered and all code has executed. The default is True. The HttpResponse class also provides low-level control over the management of the output buffer, with the Clear( ), Flush( ), and End( ) methods. You can also use the AppendToLog( ) method to write a string of information to the IIS log file on the web server. This method should not be used for debugging, as better options are provided by the TraceContext class.
public sealed class HttpResponse { // Public Constructors public HttpResponse(System.IO.TextWriter writer); // Public Instance Properties public bool Buffer{set; get; } public bool BufferOutput{set; get; } public HttpCachePolicy Cache{get; } public string CacheControl{set; get; } public string Charset{set; get; } public Encoding ContentEncoding{set; get; } public string ContentType{set; get; } public HttpCookieCollection Cookies{get; } public int Expires{set; get; } public DateTime ExpiresAbsolute{set; get; } public Stream Filter{set; get; } public bool IsClientConnected{get; } public TextWriter Output{get; } public Stream OutputStream{get; } public string RedirectLocation{set; get; } public string Status{set; get; } public int StatusCode{set; get; } public string StatusDescription{set; get; } public bool SuppressContent{set; get; } // Public Static Methods public static void RemoveOutputCacheItem(string path); // Public Instance Methods public void AddCacheItemDependencies(System.Collections.ArrayList cacheKeys); public void AddCacheItemDependency(string cacheKey); public void AddFileDependencies(System.Collections.ArrayList filenames); public void AddFileDependency(string filename); public void AddHeader(string name, string value); public void AppendCookie(HttpCookie cookie); public void AppendHeader(string name, string value); public void AppendToLog(string param); public string ApplyAppPathModifier(string virtualPath); public void BinaryWrite(byte[ ] buffer); public void Clear( ); public void ClearContent( ); public void ClearHeaders( ); public void Close( ); public void End( ); public void Flush( ); public void Pics(string value); public void Redirect(string url); public void Redirect(string url, bool endResponse); public void SetCookie(HttpCookie cookie); public void Write(char ch); public void Write(char[ ] buffer, int index, int count); public void Write(object obj); public void Write(string s); public void WriteFile(IntPtr fileHandle, long offset, long size); public void WriteFile(string filename); public void WriteFile(string filename, bool readIntoMemory); public void WriteFile(string filename, long offset, long size); }
