FileWebRequest クラス

.NET Framework クラス ライブラリ リファレンス

FileWebRequest クラス

WebRequest クラスのファイル システムの実装を提供します。

名前空間: System.Net
アセンブリ: System (system.dll 内)
構文

Visual Basic (宣言)

<SerializableAttribute> _
Public Class FileWebRequest
    Inherits WebRequest
    Implements ISerializable

Visual Basic (使用法)

Dim instance As FileWebRequest

C#

[SerializableAttribute] 
public class FileWebRequest : WebRequest, ISerializable

C++

[SerializableAttribute] 
public ref class FileWebRequest : public
 WebRequest, ISerializable

J#

/** @attribute SerializableAttribute() */ 
public class FileWebRequest extends WebRequest
 implements ISerializable

JScript

SerializableAttribute 
public class FileWebRequest extends
 WebRequest implements ISerializable

解説

FileWebRequest クラスは、file:// スキームを使用してローカル ファイルを要求する URI (Uniform Resource Identifier) に対して WebRequestabstract 基本クラスを実装します。

FileWebRequest コンストラクタは使用しないでください。FileWebRequest クラスの新しいインスタンスを初期化するには、WebRequest.Create メソッドを使用します。URI スキームが file:// である場合、Create メソッドは、FileWebRequest オブジェクトを返します。

GetResponse メソッドは、RequestUri プロパティで指定されるファイルへの同期要求を行い、応答を格納した FileWebResponse オブジェクトを返します。BeginGetResponse メソッドと EndGetResponse メソッドを使用して、ファイルへの非同期要求を可能にします。

ファイルにデータを書き込む場合、GetRequestStream メソッドは書き込み先の Stream インスタンスを返します。BeginGetRequestStream メソッドと EndGetRequestStream メソッドは、書き込みデータ ストリームへの非同期アクセスを可能にします。

FileWebRequest クラスは、エラー処理とコード アクセス セキュリティのために File クラスを使用します。

使用例

FileWebRequest クラスを使用してファイル システム リソースにアクセスするコード例を次に示します。

Visual Basic

'
' This example creates or opens a text file and stores a string in it.
 
' Both the file and the string are passed by the user.
' Note. For this program to work, the folder containing the test file
' must be shared, with its permissions set to allow write access. 

Imports System.Net
Imports System
Imports System.IO
Imports System.Text

Namespace Mssc.PluggableProtocols.File

    Module TestGetRequestStream

        Class TestGetRequestStream

            Private Shared myFileWebRequest
 As FileWebRequest

            ' Show how to use this program.
            Private Shared Sub
 showUsage()
                Console.WriteLine(ControlChars.Lf + "Please enter
 file name and timeout :")
                Console.WriteLine("Usage: vb_getrequeststream
 <systemname>/<sharedfoldername>/<filename> timeout")
                Console.WriteLine("Example: vb_getrequeststream
 ngetrequestrtream() ndpue/temp/hello.txt  1000")
                Console.WriteLine("Small time-out values (for
 example, 3 or less) cause a time-out exception.")
            End Sub

            Private Shared Sub
 makeFileRequest(ByVal fileName As String,
 ByVal timeout As Integer)
                Try
                    ' Create a Uri object.to access the file requested
 by the user. 
                    Dim myUrl As New
 Uri("file://" + fileName)

                    ' Create a FileWebRequest object.for the requeste
 file.
                    myFileWebRequest = CType(WebRequest.CreateDefault(myUrl), FileWebRequest)

                    ' Set the time-out to the value selected by the
 user.
                    myFileWebRequest.Timeout = timeout

                    ' Set the Method property to POST  
                    myFileWebRequest.Method = "POST"


                Catch e As WebException
                    Console.WriteLine(("WebException is: "
 + e.Message))
                Catch e As UriFormatException
                    Console.WriteLine(("UriFormatWebException
 is: " + e.Message))
                End Try

            End Sub

            Private Shared Sub
 writeToFile()
                Try
                    ' Enter the string to write to the file.
                    Console.WriteLine("Enter the string you want
 to write:")
                    Dim userInput As String
 = Console.ReadLine()

                    ' Convert the string to a byte array.
                    Dim encoder As New
 ASCIIEncoding
                    Dim byteArray As Byte()
 = encoder.GetBytes(userInput)

                    ' Set the ContentLength property.
                    myFileWebRequest.ContentLength = byteArray.Length

                    Dim contentLength As String
 = myFileWebRequest.ContentLength.ToString()

                    Console.WriteLine(ControlChars.Lf + "The content
 length is {0}.", contentLength)


                    ' Get the file stream handler to write to the file.
                    Dim readStream As Stream
 = myFileWebRequest.GetRequestStream()

                    ' Write to the stream. 
                    ' Note. For this to work the file must be accessible
                    ' on the network. This can be accomplished by setting
 the property
                    ' sharing of the folder containg the file.  
                    ' FileWebRequest.Credentials property cannot be
 used for this purpose.
                    readStream.Write(byteArray, 0, userInput.Length)


                    Console.WriteLine(ControlChars.Lf + "The String
 you entered was successfully written to the file.")

                    readStream.Close()

                Catch e As WebException
                    Console.WriteLine(("WebException is: "
 + e.Message))
                Catch e As UriFormatException
                    Console.WriteLine(("UriFormatWebException
 is: " + e.Message))
                End Try

            End Sub

            Public Shared Sub
 Main(ByVal args() As String)

                If args.Length < 2 Then
                    showUsage()
                Else
                    makeFileRequest(args(0), Integer.Parse(args(1)))
                    writeToFile()
                End If

            End Sub 'Main

        End Class 'TestGetRequestStream



    End Module

End Namespace

C#

// This example creates or opens a text file and stores a string in
 it. 
// Both the file and the string are passed by the user.
// Note. For this program to work, the folder containing the test file
// must be shared, with its permissions set to allow write access. 
using System.Net;
using System;
using System.IO;
using System.Text;

namespace Mssc.PluggableProtocols.File
{
    class TestGetRequestStream
    {
        private static FileWebRequest myFileWebRequest;

        private static void
 showUsage ()
        {
            Console.WriteLine ("\nPlease enter file name and timeout :");
            Console.WriteLine ("Usage: cs_getrequeststream <systemname>/<sharedfoldername>/<filename>
 timeout");
            Console.WriteLine ("Example: cs_getrequeststream ngetrequestrtream()
 ndpue/temp/hello.txt  1000");
            Console.WriteLine ("Small time-out values (for
 example, 3 or less) cause a time-out exception.");
        }

        private static void
 makeFileRequest (string fileName, int timeout)
        {
            try
            {
                // Create a Uri object. 
                Uri myUrl = new Uri ("file://"
 + fileName);

                // Create a FileWebRequest object.
                myFileWebRequest = (FileWebRequest)WebRequest.CreateDefault (myUrl);

                // Set the time-out to the value selected by the user.
                myFileWebRequest.Timeout = timeout;

                // Set the Method property to POST  
                myFileWebRequest.Method = "POST";
            }
            catch (WebException e)
            {
                Console.WriteLine ("WebException: " + e.Message);
            }
            catch (UriFormatException e)
            {
                Console.WriteLine ("UriFormatWebException: " + e.Message);
            }
        }

        private static void
 writeToFile ()
        {
            try
            {
                // Enter the string to write to the file.
                Console.WriteLine ("Enter the string you
 want to write:");

                string userInput = Console.ReadLine ();

                // Convert the string to a byte array.
                ASCIIEncoding encoder = new ASCIIEncoding ();
                byte[] byteArray = encoder.GetBytes (userInput);

                // Set the ContentLength property.
                myFileWebRequest.ContentLength = byteArray.Length;

                string contentLength = myFileWebRequest.ContentLength.ToString
 ();

                Console.WriteLine ("\nThe content length is {0}.", contentLength);

                // Get the file stream handler to write to the file.
                Stream readStream = myFileWebRequest.GetRequestStream ();

                // Write to the file stream. 
                // Note.  For this to work, the file must be accessible
                // on the network. This can be accomplished by setting
 the property
                // sharing of the folder containg the file. 
                // FileWebRequest.Credentials property cannot be used
 for this purpose.
                readStream.Write (byteArray, 0, userInput.Length);
                Console.WriteLine ("\nThe String you entered was successfully
 written to the file.");

                readStream.Close ();
            }
            catch (WebException e)
            {
                Console.WriteLine ("The WebException: " + e.Message);
            }
            catch (UriFormatException e)
            {
                Console.WriteLine ("The UriFormatWebException: " + e.Message);
            }
        }

        public static void
 Main (String[] args)
        {
            if (args.Length < 2)
                showUsage ();
            else
            {
                makeFileRequest (args[0], int.Parse (args[1]));
                writeToFile ();
            }
        }
    }
}

C++

// This program creates or open a text file in which it stores a string.
// Both file and string are passed by the user.
// Note. In order for this program to work, the folder containing the
 test file
// must be shared with its permissions set to allow write access.
#using <System.dll>

using namespace System;
using namespace System::IO;
using namespace System::Text;
using namespace System::Net;
ref class TestGetRequestStream
{
private:
   static FileWebRequest^ myFileWebRequest;
   static void showUsage()
   {
      Console::WriteLine( "\nPlease enter file name and timeout :" );
      Console::WriteLine( "Usage: cs_getrequeststream <systemname>/<sharedfoldername>/<filename>
 timeout" );
      Console::WriteLine( "Example: cs_getrequeststream ndpue/temp/hello.txt
 1000" );
      Console::WriteLine( "Small timeout values (for instance
 3 or less) cause a timeout exception." );
   }

   static void makeFileRequest( String^ fileName,
 int timeout )
   {
      try
      {
         
         // Create a Uri object.
         Uri^ myUrl = gcnew Uri( String::Format( "file://{0}",
 fileName ) );
         
         // Create a FileWebRequest object.
         myFileWebRequest = dynamic_cast<FileWebRequest^>(WebRequest::CreateDefault(
 myUrl ));
         
         // Set the timeout to the value selected by the user.
         myFileWebRequest->Timeout = timeout;
         
         // Set the Method property to POST
         myFileWebRequest->Method = "POST";
         
      }
      catch ( WebException^ e ) 
      {
         Console::WriteLine( "WebException: {0}", e->Message );
      }
      catch ( UriFormatException^ e ) 
      {
         Console::WriteLine( "UriFormatWebException: {0}", e->Message
 );
      }

   }

   static void writeToFile()
   {
      try
      {
         
         // Enter the string to write into the file.
         Console::WriteLine( "Enter the string you want to
 write:" );
         String^ userInput = Console::ReadLine();
         
         // Convert the string to Byte array.
         ASCIIEncoding^ encoder = gcnew ASCIIEncoding;
         array<Byte>^byteArray = encoder->GetBytes( userInput );
         
         // Set the ContentLength property.
         myFileWebRequest->ContentLength = byteArray->Length;
         String^ contentLength = myFileWebRequest->ContentLength.ToString();
         Console::WriteLine( "\nThe content length is {0}.", contentLength
 );
         
         // Get the file stream handler to write into the file.
         Stream^ readStream = myFileWebRequest->GetRequestStream();
         
         // Write to the file stream.
         // Note. In order for this to work the file must be accessible
         // on the network. This can be accomplished by setting the
 property
         // sharing of the folder containg the file. The permissions
         // can be set so everyone can modify the file.
         // FileWebRequest::Credentials property cannot be used for
 this purpose.
         readStream->Write( byteArray, 0, userInput->Length );
         Console::WriteLine( "\nThe String you entered was successfully written
 into the file." );
         
         readStream->Close();
      }
      catch ( WebException^ e ) 
      {
         Console::WriteLine( "The WebException: {0}", e->Message );
      }
      catch ( UriFormatException^ e ) 
      {
         Console::WriteLine( "The UriFormatWebException: {0}", e->Message
 );
      }

   }


public:
   static void Main()
   {
      array<String^>^args = Environment::GetCommandLineArgs();
      if ( args->Length < 3 )
            showUsage();
      else
      {
         makeFileRequest( args[ 1 ], Int32::Parse( args[ 2 ] ) );
         writeToFile();
      }
   }

};

int main()
{
   TestGetRequestStream::Main();
}

J#

// This example creates or opens a text file and stores a string in
 it. 
// Both the file and the string are passed by the user.
// Note. For this program to work, the folder containing the test file
// must be shared, with its permissions set to allow write access. 
import System.Net.*;
import System.*;
import System.IO.*;
import System.Text.*;

class TestGetRequestStream
{
    private static FileWebRequest myFileWebRequest;

    private static void
 ShowUsage()
    {
        Console.WriteLine("\nPlease enter file name and timeout :");
        Console.WriteLine("Usage: jsl_getrequeststream <systemname>/"
 
            + "<sharedfoldername>/<filename> timeout");
        Console.WriteLine("Example: cs_getrequeststream ngetrequestrtream()"
 
            + "ndpue/temp/hello.txt  1000");
        Console.WriteLine("Small time-out values (for example,
 3 or less) " 
            + "cause a time-out exception.");
    } //ShowUsage

    private static void
 MakeFileRequest(String fileName, int timeout)
    {
        try {
            // Create a Uri object. 
            Uri myUrl = new Uri("file://"
 + fileName);

            // Create a FileWebRequest object.
            myFileWebRequest = 
                ((FileWebRequest)(WebRequest.CreateDefault(myUrl)));

            // Set the time-out to the value selected by the user.
            myFileWebRequest.set_Timeout(timeout);
            // Set the Method property to POST  
            myFileWebRequest.set_Method("POST");
        }
        catch (WebException e) {
            Console.WriteLine(("WebException: " + e.get_Message()));
        }
        catch (UriFormatException e) {
            Console.WriteLine(("UriFormatWebException: " + e.get_Message()));
        }
    } //MakeFileRequest

    private static void
 WriteToFile()
    {
        try {
            // Enter the string to write to the file.
            Console.WriteLine("Enter the string you want
 to write:");
            String userInput = Console.ReadLine();

            // Convert the string to a byte array.
            ASCIIEncoding encoder = new ASCIIEncoding();
            ubyte byteArray[] = encoder.GetBytes(userInput);

            // Set the ContentLength property.
            myFileWebRequest.set_ContentLength(byteArray.length);
            String contentLength = 
                (new Long(myFileWebRequest.get_ContentLength())).ToString();
            Console.WriteLine("\nThe content length is {0}.", contentLength);

            // Get the file stream handler to write to the file.
            Stream readStream = myFileWebRequest.GetRequestStream();

            // Write to the file stream. 
            // Note.  For this to work, the file must be accessible
            // on the network. This can be accomplished by setting the
 property
            // sharing of the folder containg the file. 
            // FileWebRequest.Credentials property cannot be used for
 
            // this purpose.
            readStream.Write(byteArray, 0, userInput.get_Length());
            Console.WriteLine("\nThe String you entered was successfully "
 
                + "written to the file.");
            readStream.Close();
        }
        catch (WebException e) {
            Console.WriteLine(("The WebException: " + e.get_Message()));
        }
        catch (UriFormatException e) {
            Console.WriteLine(("The UriFormatWebException: " 
                + e.get_Message()));
        }
    } //WriteToFile

    public static void main(String[]
 args)
    {
        if (args.length < 2) {
            ShowUsage();
        }
        else {
            MakeFileRequest(args[0], Integer.parseInt(args[1]));
            WriteToFile();
        }
    } //main
} //TestGetRequestStream

継承階層

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

スレッド セーフ

この型の public static (Visual Basic では Shared) メンバはすべて、スレッド セーフです。インスタンス メンバの場合は、スレッド セーフであるとは限りません。

プラットフォーム

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0

参照

関連項目
FileWebRequest メンバ
System.Net 名前空間
File