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FileWebRequest.BeginGetRequestStream Method

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

Namespace: System.Net
Assembly: System (in system.dll)

public override IAsyncResult BeginGetRequestStream (
	AsyncCallback callback,
	Object state
)
public IAsyncResult BeginGetRequestStream (
	AsyncCallback callback, 
	Object state
)
public override function BeginGetRequestStream (
	callback : AsyncCallback, 
	state : Object
) : IAsyncResult
Not applicable.

Parameters

callback

The AsyncCallback delegate.

state

An object that contains state information for this request.

Return Value

An IAsyncResult that references the asynchronous request.

Exception typeCondition

ProtocolViolationException

The Method property is GET and the application writes to the stream.

InvalidOperationException

The stream is being used by a previous call to BeginGetRequestStream.

ApplicationException

No write stream is available.

The 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 EndGetRequestStream method to return the request stream.

The following code example uses BeginGetRequestStream to make an asynchronous request for a Stream object.


public class RequestDeclare
{
     public FileWebRequest myFileWebRequest;    
     public String userinput;
   
     public RequestDeclare()
    {
        myFileWebRequest = null;
    }
}

class FileWebRequest_reqbeginend
{
    public static ManualResetEvent allDone = new ManualResetEvent(false);

    static void Main(string[] args)
    {
      if (args.Length < 1)
      {
           Console.WriteLine("\nPlease enter the file name as command line parameter:");
            Console.WriteLine("Usage:FileWebRequest_reqbeginend <systemname>/<sharedfoldername>/<filename>\nExample:FileWebRequest_reqbeginend shafeeque/shaf/hello.txt");
        
      }  
      else
      {

        try
         {

              // Place a webrequest.
              WebRequest myWebRequest= WebRequest.Create("file://"+args[0]);
           
              // Create an instance of the 'RequestDeclare' and associate the 'myWebRequest' to it.        
              RequestDeclare requestDeclare = new RequestDeclare();
              requestDeclare.myFileWebRequest = (FileWebRequest)myWebRequest;
              // Set the 'Method' property of 'FileWebRequest' object to 'POST' method.
              requestDeclare.myFileWebRequest.Method="POST";
              Console.WriteLine("Enter the string you want to write into the file:");
              requestDeclare.userinput = Console.ReadLine();

              // Begin the Asynchronous request for getting file content using 'BeginGetRequestStream()' method .
              IAsyncResult r=(IAsyncResult) requestDeclare.myFileWebRequest.BeginGetRequestStream(new AsyncCallback(ReadCallback),requestDeclare);            
              allDone.WaitOne();

              Console.Read();
        }
        catch(ProtocolViolationException e)
        {
              Console.WriteLine("ProtocolViolationException is :"+e.Message);
        }
        catch(InvalidOperationException e)
        {
               Console.WriteLine("InvalidOperationException is :"+e.Message);
        }
        catch(UriFormatException e)
        {
            Console.WriteLine("UriFormatExceptionException is :"+e.Message);
         }
     }
    }

    private static void ReadCallback(IAsyncResult ar)
    {    

     try
     {

          // State of the request is asynchronous.
          RequestDeclare requestDeclare=(RequestDeclare) ar.AsyncState;
          FileWebRequest myFileWebRequest=requestDeclare.myFileWebRequest;
          String sendToFile = requestDeclare.userinput;

          // End the Asynchronus request by calling the 'EndGetRequestStream()' method.
          Stream readStream=myFileWebRequest.EndGetRequestStream(ar);
                    
          // Convert the string into byte array.
            
          ASCIIEncoding encoder = new ASCIIEncoding();
          byte[] byteArray = encoder.GetBytes(sendToFile);
        
          // Write to the stream.
          readStream.Write(byteArray,0,sendToFile.Length);
          readStream.Close();
          allDone.Set();
            
          Console.WriteLine("\nThe String you entered was successfully written into the file.");
         Console.WriteLine("\nPress Enter to continue.");    


     }
    catch(ApplicationException e)
      {
          Console.WriteLine("ApplicationException is :"+e.Message);
      }                

    }

    public FileWebRequest myFileWebRequest;
    public String userInput;

    public RequestDeclare()
    {
        myFileWebRequest = null;
    } //RequestDeclare
} //RequestDeclare

class FileWebRequestReqBeginEnd
{
    public static ManualResetEvent allDone = new ManualResetEvent(false);

    public static void main(String[] args)
    {
        if (args.length < 1) {
            Console.WriteLine("\nPlease enter the file name as command " 
                + " line parameter:");
            Console.WriteLine("Usage:FileWebRequest_reqbeginend <systemname>" 
                + "/<sharedfoldername>/<filename>\nExample:" 
                + "FileWebRequest_reqbeginend shafeeque/shaf/hello.txt");
        }
        else {
            try {
                // Place a webrequest.
                WebRequest myWebRequest = WebRequest.Create("file://" 
                    + args[0]);

                // Create an instance of the 'RequestDeclare' and associate
                // the 'myWebRequest' to it.        
                RequestDeclare requestDeclare = new RequestDeclare();
                requestDeclare.myFileWebRequest = 
                    (FileWebRequest)(myWebRequest);

                // Set the 'Method' property of 'FileWebRequest' object to
                // 'POST' method.
                requestDeclare.myFileWebRequest.set_Method("POST");
                Console.WriteLine("Enter the string you want to write into " 
                    + " the file:");
                requestDeclare.userInput = Console.ReadLine();

                // Begin the Asynchronous request for getting file content
                // using 'BeginGetRequestStream()' method .
                IAsyncResult r = (IAsyncResult)(requestDeclare.
                    myFileWebRequest.BeginGetRequestStream(new AsyncCallback(
                    ReadCallback), requestDeclare));
                allDone.WaitOne();
                Console.Read();
            }
            catch (ProtocolViolationException e) {
                Console.WriteLine("ProtocolViolationException is :" 
                    + e.get_Message());
            }
            catch (InvalidOperationException e) {
                Console.WriteLine("InvalidOperationException is :" 
                    + e.get_Message());
            }
            catch (UriFormatException e) {
                Console.WriteLine("UriFormatExceptionException is :" 
                    + e.get_Message());
            }
        }
    } //main

    private static void ReadCallback(IAsyncResult ar)
    {
        try {
            // State of the request is asynchronous.
            RequestDeclare requestDeclare = (RequestDeclare)(
                ar.get_AsyncState());
            FileWebRequest myFileWebRequest = requestDeclare.myFileWebRequest;
            String sendToFile = requestDeclare.userInput;

            // End the Asynchronus request by calling the
            // 'EndGetRequestStream()' method.
            Stream readStream = myFileWebRequest.EndGetRequestStream(ar);

            // Convert the string into byte array.
            ASCIIEncoding encoder = new ASCIIEncoding();
            ubyte byteArray[] = encoder.GetBytes(sendToFile);

            // Write to the stream.
            readStream.Write(byteArray, 0, sendToFile.get_Length());
            readStream.Close();
            allDone.Set();
            Console.WriteLine("\nThe String you entered was successfully " 
                + "written into the file.");
            Console.WriteLine("\nPress Enter to continue.");
        }
        catch (ApplicationException e) {
            Console.WriteLine("ApplicationException is :" + e.get_Message());
        }
    } //ReadCallback

Windows 98, Windows Server 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

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

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