WebRequest

WebRequestCF 1.0, ECMA 1.0, serializable, marshal by reference

System.Net (system.dll)abstract class

Because many Internet protocols are request-response synchronous protocols, this class serves as a base type for any and all request-response style of network communication. As such, a .NET programmer will never create a WebRequest type directlyinstead, a static method on this class, Create( ), is used as a "virtual constructor" to create a subtype of WebRequest that matches the protocol scheme requested. For example, if the string http://www.oreilly.com is passed to Create( ), an instance of HttpWebRequest is handed back. Out of the box, only "http", "https", and "file" are supported.

Once obtained, a .NET programmer can manipulate the common properties of the WebRequest type to control various aspects of the request. Alternatively, downcast the generic WebRequest reference to the concrete type returned to access protocol-specific aspects of that protocolfor example, the returned object from WebRequest.Create("http://www.oreilly.com") will be a HttpWebRequest, so it is safe to cast it as such. This allows access to the Accept and SendChunked properties/headers in the request. Be sure to manipulate these properties before the request is sent, or the modifications will have no effect.

Use the GetResponse( ) method to obtain a WebResponse object corresponding to the response that the remote server sent. This means that the request is sent, and the response harvested. The methods BeginGetResponse( ) and EndGetResponse( ) are asynchronous versions of GetResponse( ).

By default, WebRequest uses the proxy server specified in GlobalProxySelection.Select. Override that setting by assigning an IWebProxy implementation to the Proxy property.

public abstract class WebRequest : MarshalByRefObject, System.Runtime.Serialization.ISerializable {
// Protected Constructors
   protected WebRequest( );
   protected WebRequest(System.Runtime.Serialization.SerializationInfo serializationInfo,
       System.Runtime.Serialization.  StreamingContext streamingContext);
// Public Instance Properties
   public virtual string ConnectionGroupName{set; get; }
   public virtual long ContentLength{set; get; }
   public virtual string ContentType{set; get; }
   public virtual ICredentials Credentials{set; get; }
   public virtual WebHeaderCollection Headers{set; get; }
   public virtual string Method{set; get; }
   public virtual bool PreAuthenticate{set; get; }
   public virtual IWebProxy Proxy{set; get; }
   public virtual Uri RequestUri{get; }
   public virtual int Timeout{set; get; }
// Public Static Methods
   public static WebRequest Create(string requestUriString);
   public static WebRequest Create(Uri requestUri);
   public static WebRequest CreateDefault(Uri requestUri);
   public static bool RegisterPrefix(string prefix, IWebRequestCreate creator);
// Public Instance Methods
   public virtual void Abort( );
   public virtual IAsyncResult BeginGetRequestStream(AsyncCallback callback, object state);
   public virtual IAsyncResult BeginGetResponse(AsyncCallback callback, object state);
   public virtual Stream EndGetRequestStream(IAsyncResult asyncResult);
   public virtual WebResponse EndGetResponse(IAsyncResult asyncResult);
   public virtual Stream GetRequestStream( );
   public virtual WebResponse GetResponse( );
}

Hierarchy

System.Object System.MarshalByRefObject WebRequest(System.Runtime.Serialization.ISerializable)

Subclasses

FileWebRequest, HttpWebRequest

Returned By

IWebRequestCreate.Create( )

Passed To

AuthenticationManager.{Authenticate( ), PreAuthenticate( )}, IAuthenticationModule.{Authenticate( ), PreAuthenticate( )}, ICertificatePolicy.CheckValidationResult( )



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