System.Net.FileWebRequest Class

Summary

Provides a file system implementation of the WebRequest class.

C# Syntax:

[Serializable] public class FileWebRequest : WebRequest

The FileWebRequest class implements the WebRequestabstract base class for URIs that use the file:// scheme to request local files.

Do not use the FileWebRequest.#ctor constructor. Use the WebRequest.Create method to initialize new instances of the FileWebRequest class. If the URI scheme is file:// , the WebRequest.Create method returns a FileWebRequest instance.

The FileWebRequest.GetResponse method makes a synchronous request for the file specified in the FileWebRequest.RequestUri property and returns a FileWebResponse instance containing the response. You can make an asynchronous request for the file using the FileWebRequest.BeginGetResponse and FileWebRequest.EndGetResponse methods.

When you want to write data to a file, the FileWebRequest.GetRequestStream method returns a Stream instance to write to. The FileWebRequest.BeginGetRequestStream and FileWebRequest.EndGetRequestStream methods provide asynchronous access to the write data stream.

The FileWebRequest class relies on the File class for error handling and code access security.

System.Net Namespace | File

System.Net.FileWebRequest Member List:

Public Properties

ConnectionGroupName	Read-write Overridden: Gets or sets the name of the connection group for the request. This property is reserved for future use.
ContentLength	Read-write Overridden: Gets or sets the content length of the data being sent.
ContentType	Read-write Overridden: Gets or sets the content type of the data being sent. This property is reserved for future use.
Credentials	Read-write Overridden: Gets or sets the credentials associated with this request. This property is reserved for future use.
Headers	Read-only Overridden: Gets a collection of the name/value pairs associated with the request. This property is reserved for future use.
Method	Read-write Overridden: Gets or sets the protocol method used for the request. This property is reserved for future use.
PreAuthenticate	Read-write Overridden: Gets or sets a value indicating whether to preauthenticate a request. This property is reserved for future use.
Proxy	Read-write Overridden: Gets or sets the network proxy to use for this request. This property is reserved for future use.
RequestUri	Read-only Overridden: Gets the URI of the request.
Timeout	Read-write Overridden: Gets or sets the length of time until the request times out.

Public Methods

Abort (inherited from System.Net.WebRequest)	See base class member description: System.Net.WebRequest.Abort Cancels an asynchronous request to an Internet resource.
BeginGetRequestStream	Overridden: Begins an asynchronous request for a Stream instance to use to write data.
BeginGetResponse	Overridden: Begins an asynchronous request for a file system 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 that the application uses to write data.
EndGetResponse	Overridden: Ends an asynchronous request for a file system 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 (inherited from System.Object)	See base class member description: System.Object.GetHashCode Derived from System.Object, the primary base class for all objects.
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: Returns a Stream instance for writing data to the file system resource.
GetResponse	Overridden: Returns a response to a file system request.
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 FileWebRequest 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.

Hierarchy:

• System.Object
• System.MarshalByRefObject
• System.Net.WebRequest
• System.Net.FileWebRequest

System.Net.FileWebRequest Member Details

Summary

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

C# Syntax:

protected FileWebRequest(    SerializationInfo serializationInfo,    StreamingContext streamingContext );

serializationInfo

A SerializationInfo instance that contains the information required to serialize the new FileWebRequest instance.

streamingContext

An instance of the StreamingContext class that contains the source of the serialized stream associated with the new FileWebRequest instance.

This constructor implements the ISerializable interface for the FileWebRequest class.

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Summary

Gets or sets the name of the connection group for the request. This property is reserved for future use.

C# Syntax:

public override string ConnectionGroupName {get; set;}

The FileWebRequest.ConnectionGroupName property is currently not used by the FileWebRequest class.

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Summary

Gets or sets the content length of the data being sent.

C# Syntax:

public override long ContentLength {get; set;}

Exceptions

Exception Type	Condition
ArgumentException	FileWebRequest.ContentLength is less than 0.

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Summary

Gets or sets the content type of the data being sent. This property is reserved for future use.

C# Syntax:

public override string ContentType {get; set;}

The FileWebRequest.ContentType property contains the media type of the data being sent. This is typically the MIME encoding of the content. The FileWebRequest.ContentType property is currently not used by the FileWebRequest class.

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Summary

Gets or sets the credentials associated with this request. This property is reserved for future use.

C# Syntax:

public override ICredentials Credentials {get; set;}

Because the FileWebRequest class does not authenticate requests for files from the local file system, it ignores the contents, if any, of the FileWebRequest.Credentials property. Authentication for FileWebRequest is handled by the access control lists for the file resource in the underlying file system.

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Summary

Gets a collection of the name/value pairs associated with the request. This property is reserved for future use.

C# Syntax:

public override WebHeaderCollection Headers {get;}

The FileWebRequest.Headers property is currently not used by the FileWebRequest class.

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Summary

Gets or sets the protocol method used for the request. This property is reserved for future use.

C# Syntax:

public override string Method {get; set;}

The FileWebRequest.Method property is currently not used by the FileWebRequest class.

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Summary

Gets or sets a value indicating whether to preauthenticate a request. This property is reserved for future use.

C# Syntax:

public override bool PreAuthenticate {get; set;}

The FileWebRequest.PreAuthenticate property is currently not used by the FileWebRequest class.

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Summary

Gets or sets the network proxy to use for this request. This property is reserved for future use.

C# Syntax:

public override IWebProxy Proxy {get; set;}

The FileWebRequest.Proxy property is currently not used by the FileWebRequest class.

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Summary

Gets the URI of the request.

C# Syntax:

public override Uri RequestUri {get;}

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Summary

Gets or sets the length of time until the request times out.

C# Syntax:

public override int Timeout {get; set;}

Exceptions

Exception Type	Condition
ArgumentException	FileWebRequest.Timeout is set to less than 0.

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Inherited
See base class member description: System.Net.WebRequest.Abort

Summary

Cancels an asynchronous request to an Internet resource.

C# Syntax:

public virtual void Abort();

Exceptions

Exception Type	Condition
NotSupportedException	Any attempt is made to access the method, when the method is not overridden in a descendant class.

The WebRequest.Abort method cancels asynchronous requests to Internet resources started with the WebRequest.BeginGetResponse method.

Note The WebRequest class is an abstract class. The actual behavior of WebRequest instances at run time is determined by the descendant class returned by the WebRequest.Create method. For more information about default values and exceptions, see the documentation for the descendant classes, such as HttpWebRequest and FileWebRequest.

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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

An object containing state information for this request.

Return Value:

An IAsyncResult that references the asynchronous request.

Exceptions

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

The FileWebRequest.BeginGetRequestStream method starts an asynchronous request for a stream used to send data to a file system resource. The callback method that implements the AsyncCallback delegate uses the FileWebRequest.EndGetRequestStream method to return the request stream.

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Summary

Begins an asynchronous request for a file system resource.

C# Syntax:

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

callback

The AsyncCallback delegate.

state

An object containing state information for this request.

Return Value:

An IAsyncResult that references the asynchronous request.

Exceptions

Exception Type	Condition
InvalidOperationException	The stream is already in use by a previous call to FileWebRequest.BeginGetResponse.

The FileWebRequest.BeginGetResponse method starts an asynchronous request for a file system resource. The asynchronous callback method that implements the AsyncCallback delegate uses the FileWebRequest.EndGetResponse method to return the actual FileWebResponse.

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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 that the application uses to write data.

C# Syntax:

public override Stream EndGetRequestStream(    IAsyncResult asyncResult );

asyncResult

An IAsyncResult referencing the pending request for a stream.

Return Value:

A Stream instance that the application uses to write data.

Exceptions

Exception Type	Condition
ArgumentNullException	asyncResult is null.

The FileWebRequest.EndGetRequestStream method completes an asynchronous stream request that was started by the FileWebRequest.BeginGetRequestStream method.

Note To avoid timing issues with garbage collection, be sure to close the response stream by calling the Stream.Close method on the stream returned by FileWebResponse.GetResponseStream after calling FileWebRequest.EndGetResponse.

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Summary

Ends an asynchronous request for a file system resource.

C# Syntax:

public override WebResponse EndGetResponse(    IAsyncResult asyncResult );

asyncResult

An IAsyncResult referencing the pending request for a response.

Return Value:

A WebResponse that contains the response from the file system resource.

Exceptions

Exception Type	Condition
ArgumentNullException	asyncResult is null.

The FileWebRequest.EndGetResponse method completes an asynchronous request for a file system resource that was started with the FileWebRequest.BeginGetResponse method.

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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:

~FileWebRequest();

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.GetHashCode

C# Syntax:

public virtual int GetHashCode();

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.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

Returns a Stream instance for writing data to the file system resource.

C# Syntax:

public override Stream GetRequestStream();

Return Value:

A Stream for writing data to the file system resource.

Exceptions

Exception Type	Condition
WebException	The request times out.

The FileWebRequest.GetRequestStream method returns a Stream instance for writing data to the file system resource.

The FileWebRequest.GetRequestStream method provides synchronous access to the Stream. For asynchronous access, use the FileWebRequest.BeginGetRequestStream and FileWebRequest.EndGetRequestStream methods.

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Summary

Returns a response to a file system request.

C# Syntax:

public override WebResponse GetResponse();

Return Value:

A WebResponse that contains the response from the file system resource.

Exceptions

Exception Type	Condition
WebException	The request timed out.

The FileWebRequest.GetResponse method returns a WebResponse instance containing the response from the file system resource.

The FileWebRequest.GetResponse method provides synchronous access to the WebResponse. For asynchronous access, use the FileWebRequest.BeginGetResponse and FileWebRequest.EndGetResponse methods.

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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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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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