System.Net.HttpWebRequest Class

Summary

Provides an HTTP-specific implementation of the WebRequest class.

C# Syntax:

[Serializable] public class HttpWebRequest : WebRequest

The HttpWebRequest class provides support for the properties and methods defined in WebRequest and for additional properties and methods that enable the user to interact directly with servers using HTTP.

Do not use the HttpWebRequest.#ctor constructor. Use the WebRequest.Create method to initialize new HttpWebRequest instances. If the scheme for the URI is http:// or https:// , WebRequest.Create returns an HttpWebRequest instance.

The HttpWebRequest.GetResponse method makes a synchronous request to the Internet resource specified in the HttpWebRequest.RequestUri property and returns an HttpWebResponse instance containing the response. You can make an asynchronous request to the Internet resource using the HttpWebRequest.BeginGetResponse and HttpWebRequest.EndGetResponse methods.

When you want to send data to the Internet resource, the HttpWebRequest.GetRequestStream method returns a Stream instance to use to send data. The HttpWebRequest.BeginGetRequestStream and HttpWebRequest.EndGetRequestStream methods provide asynchronous access to the send data stream.

The HttpWebRequest class throws a WebException when errors occur while accessing an Internet resource. The WebException.Status property is one of the WebExceptionStatus values that indicates the source of the error. When WebException.Status is WebExceptionStatus.ProtocolError, the WebException.Response property contains the HttpWebResponse received from the Internet resource.

HttpWebRequest exposes common HTTP header values sent to the Internet resource as properties, set by methods, or set by the system; the following table contains a complete list. You can set other headers in the HttpWebRequest.Headers property as name/value pairs.

The following table lists the HTTP headers that are set either by properties or methods or the system.

Header	Set by
Accept	Set by the HttpWebRequest.Accept property.
Connection	Set by the HttpWebRequest.Connection property, HttpWebRequest.KeepAlive property.
Content-Length	Set by the HttpWebRequest.ContentLength property.
Content-Type	Set by the HttpWebRequest.ContentType property.
Expect	Set by the HttpWebRequest.Expect property.
Date	Set by the system to current date.
Host	Set by the system to current host information.
If-Modified-Since	Set by the HttpWebRequest.IfModifiedSince property.
Range	Set by the HttpWebRequest.AddRange method.
Referer	Set by the HttpWebRequest.Referer property.
Transfer-Encoding	Set by the HttpWebRequest.TransferEncoding property or the HttpWebRequest.SendChunked property.
User-Agent	Set by the HttpWebRequest.UserAgent property.

Note HttpWebRequest is registered automatically. You do not need to call WebRequest.RegisterPrefix to register HttpWebRequest before using URIs beginning with http:// or https:// .

The following example creates an HttpWebRequest for the URI http://www.contoso.com/ .

 HttpWebRequest myReq =
 (HttpWebRequest)WebRequest.Create("http://www.contoso.com/");
 

    

System.Net Namespace

System.Net.HttpWebRequest Member List:

Public Properties

Accept	Read-write Gets or sets the value of the Accept HTTP header.
Address	Read-only Gets the URI of the Internet resource that actually responds to the request.
AllowAutoRedirect	Read-write Gets or sets a value that indicates whether the request should follow redirection responses.
AllowWriteStreamBuffering	Read-write Gets or sets a value that indicates whether to buffer the data sent to the Internet resource.
Connection	Read-write Gets or sets the value of the Connection HTTP header.
ConnectionGroupName	Read-write Overridden: Gets or sets the name of the connection group for the request.
ContentLength	Read-write Overridden: Gets or sets the Content-length HTTP header.
ContentType	Read-write Overridden: Gets or sets the value of the Content-type HTTP header.
ContinueDelegate	Read-write Gets or sets the delegate method called when an HTTP 100-continue response is received from the Internet resource.
CookieContainer	Read-write Gets or sets the cookies associated with the request.
Credentials	Read-write Overridden: Provides authentication information for the request.
Expect	Read-write Gets or sets the value of the Expect HTTP header.
HaveResponse	Read-only Gets a value indicating whether a response has been received from an Internet resource.
Headers	Read-write Overridden: Gets a collection of the name/value pairs that make up the HTTP headers.
IfModifiedSince	Read-write Gets or sets the value of the If-Modified-Since HTTP header.
KeepAlive	Read-write Gets or sets a value indicating whether to make a persistent connection to the Internet resource.
MaximumAutomaticRedirections	Read-write Gets or sets the maximum number of redirects that the request will follow.
MediaType	Read-write Gets or sets the media type of the request.
Method	Read-write Overridden: Gets or sets the method for the request.
Pipelined	Read-write Gets or sets a value indicating whether to pipeline the request to the Internet resource.
PreAuthenticate	Read-write Overridden: Gets or sets a value indicating whether to send a preauthentication header with the request.
ProtocolVersion	Read-write Gets or sets the version of HTTP to use for the request.
Proxy	Read-write Overridden: Gets or sets proxy information for the request.
Referer	Read-write Gets or sets the value of the Referer HTTP header.
RequestUri	Read-only Overridden: Gets the original URI of the request.
SendChunked	Read-write Gets or sets a value indicating whether to send data in segments to the Internet resource.
ServicePoint	Read-only Gets the service point to use for the request.
Timeout	Read-write Overridden: Gets or sets the time-out value for a request.
TransferEncoding	Read-write Gets or sets the value of the Transfer-encoding HTTP header.
UserAgent	Read-write Gets or sets the value of the User-agent HTTP header.

Public Methods

Abort	Overridden: Cancels a request to an Internet resource.
AddRange	Overloaded: AddRange(int range) Adds a byte range header to a request for a specific range from the beginning or end of the requested data.
AddRange	Overloaded: AddRange(int from, int to) Adds a byte range header to the request for a specified range.
AddRange	Overloaded: AddRange(string rangeSpecifier, int range) Adds a range header to a request for a specific range from the beginning or end of the requested data.
AddRange	Overloaded: AddRange(string rangeSpecifier, int from, int to) Adds a range header to a request for a specified range.
BeginGetRequestStream	Overridden: Begins an asynchronous request for a Stream instance to use to write data.
BeginGetResponse	Overridden: Begins an asynchronous request to an Internet resource.
CreateObjRef (inherited from System.MarshalByRefObject)	See base class member description: System.MarshalByRefObject.CreateObjRef Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.
EndGetRequestStream	Overridden: Ends an asynchronous request for a Stream instance to use to write data.
EndGetResponse	Overridden: Ends an asynchronous request to an Internet resource..
Equals (inherited from System.Object)	See base class member description: System.Object.Equals Derived from System.Object, the primary base class for all objects.
GetHashCode	Overridden: Gets the hash code for this HttpWebRequest.
GetLifetimeService (inherited from System.MarshalByRefObject)	See base class member description: System.MarshalByRefObject.GetLifetimeService Retrieves the current lifetime service object that controls the lifetime policy for this instance.
GetRequestStream	Overridden: Gets a Stream instance to use to write request data.
GetResponse	Overridden: Returns a response from an Internet resource.
GetType (inherited from System.Object)	See base class member description: System.Object.GetType Derived from System.Object, the primary base class for all objects.
InitializeLifetimeService (inherited from System.MarshalByRefObject)	See base class member description: System.MarshalByRefObject.InitializeLifetimeService Obtains a lifetime service object to control the lifetime policy for this instance.
ToString (inherited from System.Object)	See base class member description: System.Object.ToString Derived from System.Object, the primary base class for all objects.

Protected Constructors

ctor #1

Initializes a new instance of the HttpWebRequest class from the specified instances of the SerializationInfo and StreamingContext classes.

Protected Methods

Finalize (inherited from System.Object)	See base class member description: System.Object.Finalize Derived from System.Object, the primary base class for all objects.
MemberwiseClone (inherited from System.Object)	See base class member description: System.Object.MemberwiseClone Derived from System.Object, the primary base class for all objects.

Explicit Interface Implementations 

ISerializable.GetObjectData

Populates a SerializationInfo with the data needed to serialize the target object.

Hierarchy:

• System.Object
• System.MarshalByRefObject
• System.Net.WebRequest
• System.Net.HttpWebRequest

System.Net.HttpWebRequest Member Details

Summary

Initializes a new instance of the HttpWebRequest class from the specified instances of the SerializationInfo and StreamingContext classes.

C# Syntax:

protected HttpWebRequest(    SerializationInfo serializationInfo,    StreamingContext streamingContext );

serializationInfo

A SerializationInfo instance containing the information required to serialize the new HttpWebRequest instance.

streamingContext

A StreamingContext instance containing the source and destination of the serialized stream associated with the new HttpWebRequest instance.

This constructor implements the ISerializable interface for the HttpWebRequest class.

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Summary

Gets or sets the value of the Accept HTTP header.

C# Syntax:

public string Accept {get; set;}

Exceptions

Exception Type	Condition
InvalidOperationException	The request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.

To clear the Accept HTTP header, set the HttpWebRequest.Accept property to null.

Changing the HttpWebRequest.Accept property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Gets the URI of the Internet resource that actually responds to the request.

C# Syntax:

public Uri Address {get;}

The HttpWebRequest.Address property is set to the URI that actually responds to a request, after any redirections that might happen during the request are complete.

The URI of the original request is kept in the HttpWebRequest.RequestUri property.

The following example checks to see if the HttpWebRequest instance req was redirected to another location to fulfill the request, and sets the value of the hasChanged variable to true if the request was redirected; otherwise hasChanged is set to false.

bool hasChanged = (req.RequestUri != req.Address);
 

    

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Summary

Gets or sets a value that indicates whether the request should follow redirection responses.

C# Syntax:

public bool AllowAutoRedirect {get; set;}

Set HttpWebRequest.AllowAutoRedirect to true if you want the request to automatically follow HTTP redirection headers to the new location of the resource. The maximum number of redirections to follow is set by the HttpWebRequest.MaximumAutomaticRedirections property.

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Summary

Gets or sets a value that indicates whether to buffer the data sent to the Internet resource.

C# Syntax:

public bool AllowWriteStreamBuffering {get; set;}

When HttpWebRequest.AllowWriteStreamBuffering is true, the data is buffered in memory so it is ready to be resent in the event of redirections or authentication requests.

Notes to implementors: Setting HttpWebRequest.AllowWriteStreamBufferingtrue might cause performance problems when uploading large datasets because the data buffer could use all available memory.

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Summary

Gets or sets the value of the Connection HTTP header.

C# Syntax:

public string Connection {get; set;}

Exceptions

Exception Type	Condition
ArgumentException	The value of HttpWebRequest.Connection is set to Keep-alive or Close.

The request sends the HttpWebRequest.Connection property to the Internet resource as the Connection HTTP header. If HttpWebRequest.KeepAlive is true, the value "Keep-alive" is appended to the end of the Connection header.

To clear the Connection HTTP header, set the HttpWebRequest.Connection property to null.

Changing the HttpWebRequest.Connection property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Gets or sets the name of the connection group for the request.

C# Syntax:

public override string ConnectionGroupName {get; set;}

The HttpWebRequest.ConnectionGroupName property enables you to associate a request with a connection group. This is useful when your application makes requests to one server for different users, such as a Web site that retrieves customer information from a database server.

Notes to implementors: Each connection group creates additional connections for a server. This may result in exceeding ServicePoint.ConnectionLimit for that server.

The following example show how to use user information to form a connection group, assuming that the variables username, password, and domain are set by the application before this code is called.

 //Create a WebRequest.
 WebRequest WReq = WebRequest.Create("http://www.contoso.com/");
 
 // Set the authentication credentials for the request.
 WReq.Credentials = new NetworkCredential(username, password, domain);
 // Assign the request to a connection group based on the user's name
 WReq.ConnectionGroupName = username;
 
 //Get the response
 WebResponse WResp = WReq.GetResponse();

 //Use the response, then close.
 WResp.Close();
    

    

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Summary

Gets or sets the Content-length HTTP header.

C# Syntax:

public override long ContentLength {get; set;}

Exceptions

Exception Type	Condition
InvalidOperationException	The request has been started by calling the HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.
ArgumentOutOfRangeException	The new HttpWebRequest.ContentLength value is less than 0.

The HttpWebRequest.ContentLength property contains the value to send as the Content-length HTTP header with the request.

Any value other than -1 in the HttpWebRequest.ContentLength property indicates that the request will upload data and that only methods that upload data are allowed to be set in the HttpWebRequest.Method property.

Once the HttpWebRequest.ContentLength property is set to a value, that number of bytes must be written to the request stream that is returned by calling HttpWebRequest.GetRequestStream or both HttpWebRequest.BeginGetRequestStream and HttpWebRequest.EndGetRequestStream.

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Summary

Gets or sets the value of the Content-type HTTP header.

C# Syntax:

public override string ContentType {get; set;}

Exceptions

Exception Type	Condition
InvalidOperationException	The request has been started by calling the HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.

The HttpWebRequest.ContentType property contains the media type of the request. Values assigned to the HttpWebRequest.ContentType property replace any existing contents when the request sends the Content-type HTTP header.

To clear the Content-type HTTP header, set the HttpWebRequest.ContentType property to null.

Changing the HttpWebRequest.ContentType property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Gets or sets the delegate method called when an HTTP 100-continue response is received from the Internet resource.

C# Syntax:

public HttpContinueDelegate ContinueDelegate {get; set;}

The HttpWebRequest.ContinueDelegate property specifies the callback method to call when the client receives a 100-Continue response.

When the HttpWebRequest.ContinueDelegate property is set, the client calls the delegate whenever protocol responses of type HttpStatusCode.Continue (100) are received. This is useful if you want the client to display the status of the data being received from the Internet resource.

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Summary

Gets or sets the cookies associated with the request.

C# Syntax:

public CookieContainer CookieContainer {get; set;}

The HttpWebRequest.CookieContainer property provides an instance of the CookieContainer class that contains the cookies associated with this request.

HttpWebRequest.CookieContainer is null by default. You must assign a CookieContainer instance to the property to have cookies returned in the HttpWebResponse.Cookies property of the HttpWebResponse returned by HttpWebRequest.GetResponse.

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Summary

Provides authentication information for the request.

C# Syntax:

public override ICredentials Credentials {get; set;}

The HttpWebRequest.Credentials property contains authentication information to identify the maker of the request. The HttpWebRequest.Credentials property can be either an instance of NetworkCredential, in which case the user, password, and domain information contained in the NetworkCredential instance is used to authenticate the request, or it can be an instance of CredentialCache, in which case the uniform resource identifier (URI) of the request is used to determine the user, password, and domain information to use to authenticate the request.

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Summary

Gets or sets the value of the Expect HTTP header.

C# Syntax:

public string Expect {get; set;}

Exceptions

Exception Type	Condition
ArgumentException	Expect is set to "100-continue".
InvalidOperationException	The request has been started by calling the HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.

By default, HttpWebRequest.Expect is set to "100-continue". You can add other values to the list that HttpWebRequest.Expect maintains, or you can delete all values except "100-continue" from the list by setting HttpWebRequest.Expect to null.

Changing the HttpWebRequest.Expect property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Gets a value indicating whether a response has been received from an Internet resource.

C# Syntax:

public bool HaveResponse {get;}

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Summary

Gets a collection of the name/value pairs that make up the HTTP headers.

C# Syntax:

public override WebHeaderCollection Headers {get; set;}

Exceptions

Exception Type	Condition
InvalidOperationException	The request has been started by calling the HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.

The HttpWebRequest.Headers collection contains the protocol headers associated with the request. The following table lists the HTTP headers that are not stored in the HttpWebRequest.Headers collection but are either set by the system or set by properties or methods.

Header	Set by
Accept	Set by the HttpWebRequest.Accept property.
Connection	Set by the HttpWebRequest.Connection property and HttpWebRequest.KeepAlive property.
Content-Length	Set by the HttpWebRequest.ContentLength property.
Content-Type	Set by the HttpWebRequest.ContentType property.
Expect	Set by the HttpWebRequest.Expect property.
Date	Set by the system to the current date.
Host	Set by the system to the current host information.
If-Modified-Since	Set by the HttpWebRequest.IfModifiedSince property.
Range	Set by the HttpWebRequest.AddRange method.
Referer	Set by the HttpWebRequest.Referer property.
Transfer-Encoding	Set by the HttpWebRequest.TransferEncoding property or the HttpWebRequest.SendChunked property.
User-Agent	Set by the HttpWebRequest.UserAgent property.

The WebHeaderCollection.Add method throws an ArgumentException if you set one of these protected headers.

Changing the HttpWebRequest.Headers property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Gets or sets the value of the If-Modified-Since HTTP header.

C# Syntax:

public DateTime IfModifiedSince {get; set;}

Exceptions

Exception Type	Condition
InvalidOperationException	The request has been started by calling the HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.

The HttpWebRequest.IfModifiedSince property is assumed to be local time.

Changing the HttpWebRequest.IfModifiedSince property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Gets or sets a value indicating whether to make a persistent connection to the Internet resource.

C# Syntax:

public bool KeepAlive {get; set;}

Exceptions

Exception Type	Condition
InvalidOperationException	The request has been started by calling the HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.

Set this property to true to send an Connection HTTP header with the value Keep-alive. An application uses HttpWebRequest.KeepAlive to indicate a preference for persistent connections. When the HttpWebRequest.KeepAlive property is true, the application makes persistent connections to the servers that support them.

Note When using HTTP/1.1, Keep-Alive is on by default. Setting HttpWebRequest.KeepAlive false may result in sending a Connection: Close header to the server.

Changing the HttpWebRequest.KeepAlive property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Gets or sets the maximum number of redirects that the request will follow.

C# Syntax:

public int MaximumAutomaticRedirections {get; set;}

Exceptions

Exception Type	Condition
ArgumentException	The value is set to 0 or less.

The HttpWebRequest.MaximumAutomaticRedirections method property sets the maximum number of redirections for the request to follow if the HttpWebRequest.AllowAutoRedirect property is true.

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Summary

Gets or sets the media type of the request.

C# Syntax:

public string MediaType {get; set;}

Exceptions

Exception Type	Condition
InvalidOperationException	The request has been started by calling the HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.

The value of the HttpWebRequest.MediaType property affects the HttpWebResponse.CharacterSet property. When you set the HttpWebRequest.MediaType in the request, the corresponding media type is chosen from the list of character sets returned in the response Content-type HTTP header.

Changing the HttpWebRequest.MediaType property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Gets or sets the method for the request.

C# Syntax:

public override string Method {get; set;}

Exceptions

Exception Type	Condition
ArgumentException	No method is supplied -or- the method string contains invalid characters.
InvalidOperationException	The request has been started by calling the HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.

The HttpWebRequest.Method property can be set to any of the HTTP 1.1 protocol verbs: GET, HEAD, POST, PUT, DELETE, TRACE, or OPTIONS.

If the HttpWebRequest.ContentLength property is set to any value other than -1, the HttpWebRequest.Method property must be set to a protocol property that uploads data.

Changing the HttpWebRequest.Method property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Gets or sets a value indicating whether to pipeline the request to the Internet resource.

C# Syntax:

public bool Pipelined {get; set;}

An application uses the HttpWebRequest.Pipelined property to indicate a preference for pipelined connections. When HttpWebRequest.Pipelined is true, an application makes pipelined connections to the servers that support them.

Pipelined connections are made only when the HttpWebRequest.KeepAlive property is also true.

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Summary

Gets or sets a value indicating whether to send a preauthentication header with the request.

C# Syntax:

public override bool PreAuthenticate {get; set;}

When HttpWebRequest.PreAuthenticate is true and credentials are supplied, the WWW-authenticate HTTP header is sent with the initial request if its value is known; otherwise the request uses standard authentication procedures. If the authentication scheme does not support preauthentication, this property is ignored.

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Summary

Gets or sets the version of HTTP to use for the request.

C# Syntax:

public Version ProtocolVersion {get; set;}

Exceptions

Exception Type	Condition
ArgumentException	The HTTP version is set to a value other than 1.0 or 1.1.

The HttpWebRequest class supports only versions 1.0 and 1.1 of HTTP. Setting HttpWebRequest.ProtocolVersion to a different version throws an exception.

Note To set the HTTP version of the current request, use the HttpVersion.Version10 and HttpVersion.Version11 fields of the HttpVersion class.

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Summary

Gets or sets proxy information for the request.

C# Syntax:

public override IWebProxy Proxy {get; set;}

Exceptions

Exception Type	Condition
ArgumentNullException	HttpWebRequest.Proxy is set to null.

The HttpWebRequest.Proxy property identifies the WebProxy instance to use to process requests to Internet resources. To specify that no proxy should be used, set the HttpWebRequest.Proxy property to the proxy instance returned by the GlobalProxySelection.GetEmptyWebProxy method.

WebPermission to get or set the HttpWebRequest.Proxy property. Associated enumeration: PermissionState.Unrestricted.

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Summary

Gets or sets the value of the Referer HTTP header.

C# Syntax:

public string Referer {get; set;}

Exceptions

Exception Type	Condition
InvalidOperationException	The request has been started by calling the HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.

If the HttpWebRequest.AllowAutoRedirect property is true, the HttpWebRequest.Referer property is set automatically when the request is redirected to another site.

To clear the Referer HTTP header, set the HttpWebRequest.Referer property to null.

Changing the HttpWebRequest.Referer property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Gets the original URI of the request.

C# Syntax:

public override Uri RequestUri {get;}

The Uri instance passed to HttpWebRequest by the call to WebRequest.Create.

Following a redirection header does not change the HttpWebRequest.RequestUri property. To get the actual URI that responded to the request, examine the HttpWebRequest.Address property.

The following example checks to see if the HttpWebRequest instance req was redirected to another location to fulfill the request, and sets the value of the hasChanged variable to true if the request was redirected; otherwise hasChanged is set to false.

bool hasChanged = (req.RequestUri != req.Address);
 

    

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Summary

Gets or sets a value indicating whether to send data in segments to the Internet resource.

C# Syntax:

public bool SendChunked {get; set;}

Exceptions

Exception Type	Condition
InvalidOperationException	The request has been started by calling the HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.

When HttpWebRequest.SendChunked is true, the request sends data to the Internet resource in segments. The Internet resource must support receiving chunked data.

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Summary

Gets the service point to use for the request.

C# Syntax:

public ServicePoint ServicePoint {get;}

The value of the HttpWebRequest.ServicePoint property is null until the HttpWebRequest.GetResponse method is called. The ServicePoint.Address property may be different from HttpWebRequest.Address if the request is redirected.

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Summary

Gets or sets the time-out value for a request.

C# Syntax:

public override int Timeout {get; set;}

HttpWebRequest.Timeout is the number of milliseconds that a synchronous request made with the HttpWebRequest.GetResponse method waits for a response, and the HttpWebRequest.GetRequestStream methods waits for a stream. If a resource does not respond within the time-out period, the request throws a WebException with the WebException.Status property set to WebExceptionStatus.Timeout.

The HttpWebRequest.Timeout property has no effect on asynchronous requests made with the HttpWebRequest.GetResponse or HttpWebRequest.BeginGetRequestStream methods.

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Summary

Gets or sets the value of the Transfer-encoding HTTP header.

C# Syntax:

public string TransferEncoding {get; set;}

Exceptions

Exception Type	Condition
InvalidOperationException	HttpWebRequest.TransferEncoding is set when HttpWebRequest.SendChunked is false.
ArgumentException	HttpWebRequest.TransferEncoding is set to the value "Chunked".

Before you can set the HttpWebRequest.TransferEncoding property, you must first set the HttpWebRequest.SendChunked property to true. Clearing HttpWebRequest.TransferEncoding by setting it to null has no effect on the value of HttpWebRequest.SendChunked.

Values assigned to the HttpWebRequest.TransferEncoding property replace any existing contents.

Changing the HttpWebRequest.TransferEncoding property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Gets or sets the value of the User-agent HTTP header.

C# Syntax:

public string UserAgent {get; set;}

Exceptions

Exception Type	Condition
InvalidOperationException	The request has been started by calling the HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method.

Changing the HttpWebRequest.UserAgent property after the request has been started by calling HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, HttpWebRequest.GetResponse, or HttpWebRequest.BeginGetResponse method will throw an InvalidOperationException.

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Summary

Cancels a request to an Internet resource.

C# Syntax:

public override void Abort();

HttpWebRequest.Abort cancels a request to a resource. After a request is canceled, calling HttpWebRequest.GetResponse, HttpWebRequest.BeginGetResponse, HttpWebRequest.EndGetResponse, HttpWebRequest.GetRequestStream, HttpWebRequest.BeginGetRequestStream, or HttpWebRequest.EndGetRequestStream will cause a WebException with WebException.Status set to WebExceptionStatus.RequestCanceled.

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Summary

Adds a byte range header to a request for a specific range from the beginning or end of the requested data.

C# Syntax:

public void AddRange(    int range );

range

The starting or ending point of the range.

HttpWebRequest.AddRange adds a byte range header to the request.

If range is positive, the range is from the start of the data to range.

If range is negative, the range is from range to the end of the data.

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Summary

Adds a byte range header to the request for a specified range.

C# Syntax:

public void AddRange(    int from,    int to );

from

The position at which to start sending data.

to

The position at which to stop sending data.

Exceptions

Exception Type	Condition
ArgumentOutOfRangeException	from is greater than to -or- from or to is less than 0.

HttpWebRequest.AddRange adds a byte range header to the request.

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Summary

Adds a range header to a request for a specific range from the beginning or end of the requested data.

C# Syntax:

public void AddRange(    string rangeSpecifier,    int range );

rangeSpecifier

The description of the range.

range

The starting or ending point of the range.

Exceptions

Exception Type	Condition
ArgumentNullException	rangeSpecifier is null.
ArgumentException	rangeSpecifier is invalid.
InvalidOperationException	The range header could not be added.

If range is positive, the range is from the start of the data to range.

If range is negative, the range is from range to the end of the data.

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Summary

Adds a range header to a request for a specified range.

C# Syntax:

public void AddRange(    string rangeSpecifier,    int from,    int to );

rangeSpecifier

The description of the range.

from

The position at which to start sending data.

to

The position at which to stop sending data.

Exceptions

Exception Type	Condition
ArgumentNullException	rangeSpecifier is null.
ArgumentOutOfRangeException	from is greater than to -or- from or to is less than 0.
ArgumentException	rangeSpecifier is invalid.
InvalidOperationException	The range header could not be added.

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Summary

Begins an asynchronous request for a Stream instance to use to write data.

C# Syntax:

public override IAsyncResult BeginGetRequestStream(    AsyncCallback callback,    object state );

callback

The AsyncCallback delegate.

state

The state object for this request.

Return Value:

An IAsyncResult that references the asynchronous request.

Exceptions

Exception Type	Condition
ProtocolViolationException	The HttpWebRequest.Method property is GET and the application writes to the stream.
InvalidOperationException	The stream is being used by a previous call to HttpWebRequest.BeginGetRequestStream.
ApplicationException	No write stream is available.

The HttpWebRequest.BeginGetRequestStream method starts an asynchronous request for a stream used to send data for the HttpWebRequest. The asynchronous callback method uses the HttpWebRequest.EndGetRequestStream method to return the actual stream.

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Summary

Begins an asynchronous request to an Internet resource.

C# Syntax:

public override IAsyncResult BeginGetResponse(    AsyncCallback callback,    object state );

callback

The AsyncCallback delegate

state

The state object for this request.

Return Value:

An IAsyncResult that references the asynchronous request for a response.

Exceptions

Exception Type	Condition
InvalidOperationException	The stream is already in use by a previous call to HttpWebRequest.BeginGetResponse -or- HttpWebRequest.TransferEncoding is set to a value and HttpWebRequest.SendChunked is false.
ProtocolViolationException	HttpWebRequest.Method is GET and either HttpWebRequest.ContentLength is greater than zero or HttpWebRequest.SendChunked is true. -or- HttpWebRequest.KeepAlive is true, HttpWebRequest.AllowWriteStreamBuffering is false, and either HttpWebRequest.ContentLength is greater than zero or HttpWebRequest.SendChunked is true.

The HttpWebRequest.BeginGetResponse method starts an asynchronous request for a response from the Internet resource. The asynchronous callback method uses the HttpWebRequest.EndGetResponse method to return the actual WebResponse.

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Inherited
See base class member description: System.MarshalByRefObject.CreateObjRef

Summary

Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.

C# Syntax:

public virtual ObjRef CreateObjRef(    Type requestedType );

requestedType

The Type of the object that the new ObjRef will reference.

Return Value:

Information required to generate a proxy.

Exceptions

Exception Type	Condition
RemotingException	This instance is not a valid remoting object.

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Summary

Ends an asynchronous request for a Stream instance to use to write data.

C# Syntax:

public override Stream EndGetRequestStream(    IAsyncResult asyncResult );

asyncResult

The pending request for a stream.

Return Value:

A Stream to use to write request data.

Exceptions

Exception Type	Condition
ArgumentNullException	asyncResult is null.
IOException	The request did not complete, and no stream is available.
WebException	An error occurs while processing the request.

The HttpWebRequest.EndGetRequestStream method completes an asynchronous request for a stream that was started by the HttpWebRequest.BeginGetRequestStream method. Once the Stream instance has been returned, you can send data with the HttpWebRequest by using the Stream.Write method.

Note You must set the value of the HttpWebRequest.ContentLength property before writing data to the stream. You must call the Stream.Close method to close the stream and release the connection for reuse. Failure to close the stream will cause your application to run out of connections.

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Summary

Ends an asynchronous request to an Internet resource..

C# Syntax:

public override WebResponse EndGetResponse(    IAsyncResult asyncResult );

asyncResult

The pending request for a response.

Return Value:

A WebResponse containing the response from the Internet resource.

Exceptions

Exception Type	Condition
ArgumentNullException	AsyncResult is null.
InvalidOperationException	The HttpWebRequest.ContentLength property is greater than 0 but the data has not been written to the request stream.
WebException	An error occurs while processing the request.

The HttpWebRequest.EndGetResponse method completes an asynchronous request for an Internet resource that was started by calling HttpWebRequest.BeginGetResponse.

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Inherited
See base class member description: System.Object.Equals

C# Syntax:

public virtual bool Equals(    object obj );

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.Finalize

C# Syntax:

~HttpWebRequest();

For more information on members inherited from System.Object click on the link above.

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Summary

Gets the hash code for this HttpWebRequest.

C# Syntax:

public override int GetHashCode();

Return Value:

The hash code for the HttpWebRequest.

The hash codes for HttpWebRequest A and B are guaranteed to be the same when A.Equals(B) is true.

This method implements the Object.GetHashCode.

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Inherited
See base class member description: System.MarshalByRefObject.GetLifetimeService

Summary

Retrieves the current lifetime service object that controls the lifetime policy for this instance.

C# Syntax:

public object GetLifetimeService();

Return Value:

An object of type ILease used to control the lifetime policy for this instance.

For more information about lifetime services, see the LifetimeServices class.

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Summary

Gets a Stream instance to use to write request data.

C# Syntax:

public override Stream GetRequestStream();

Return Value:

A Stream to use to write request data.

Exceptions

Exception Type	Condition
ProtocolViolationException	The HttpWebRequest.Method property is GET and the application writes to the stream.
InvalidOperationException	The HttpWebRequest.GetRequestStream method is called more than once.
WebException	An error occurs while processing the request.

The HttpWebRequest.GetRequestStream method returns a stream to use to send data for the HttpWebRequest. Once the Stream instance has been returned, you can send data with the HttpWebRequest by using the Stream.Write method.

Note You must set the value of the HttpWebRequest.ContentLength property before writing data to the stream. You must call the Stream.Close method to close the stream and release the connection for reuse. Failure to close the stream will cause your application to run out of connections.

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Summary

Returns a response from an Internet resource.

C# Syntax:

public override WebResponse GetResponse();

Return Value:

A WebResponse containing the response from the Internet resource.

Exceptions

Exception Type	Condition
WebException	The time-out period for the request expires -or- an error occurs while processing the request.

The HttpWebRequest.GetResponse method returns a WebResponse instance containing the response from the Internet resource. The actual instance returned is an instance of HttpWebResponse, and can be typecast to that class to access HTTP-specific properties.

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Inherited
See base class member description: System.Object.GetType

C# Syntax:

public Type GetType();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.MarshalByRefObject.InitializeLifetimeService

Summary

Obtains a lifetime service object to control the lifetime policy for this instance.

C# Syntax:

public virtual object InitializeLifetimeService();

Return Value:

An object of type ILease used to control the lifetime policy for this instance. This is the current lifetime service object for this instance if one exists; otherwise, a new lifetime service object initialized to the value of the LifetimeServices.LeaseManagerPollTime property.

For more information about lifetime services, see the LifetimeServices class.

The following code example demonstrates creating a lease.

 public class MyClass : MarshalByRefObject
 {
   public override Object InitializeLifetimeService()
   {
     ILease lease = (ILease)base.InitializeLifetimeService();
     if (lease.CurrentState == LeaseState.Initial)
     {
          lease.InitialLeaseTime = TimeSpan.FromMinutes(1);
          lease.SponsorshipTimeout = TimeSpan.FromMinutes(2);
           lease.RenewOnCallTime = TimeSpan.FromSeconds(2);
     }
       return lease;
   }
 }

    

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Inherited
See base class member description: System.Object.MemberwiseClone

C# Syntax:

protected object MemberwiseClone();

For more information on members inherited from System.Object click on the link above.

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Summary

Populates a SerializationInfo with the data needed to serialize the target object.

C# Syntax:

void ISerializable.GetObjectData(    SerializationInfo serializationInfo,    StreamingContext streamingContext );

serializationInfo

The SerializationInfo to populate with data.

streamingContext

The destination (see StreamingContext) for this serialization.

Implements:

ISerializable.GetObjectData

Any objects included in the SerializationInfo are automatically tracked and serialized by the formatter.

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Inherited
See base class member description: System.Object.ToString

C# Syntax:

public virtual string ToString();

For more information on members inherited from System.Object click on the link above.

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