FileWebRequest.EndGetRequestStream(IAsyncResult) 方法
定义
重要
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结束对 Stream 实例的异步请求,应用程序使用该实例写入数据。
public:
override System::IO::Stream ^ EndGetRequestStream(IAsyncResult ^ asyncResult);
public override System.IO.Stream EndGetRequestStream(IAsyncResult asyncResult);
override this.EndGetRequestStream : IAsyncResult -> System.IO.Stream
Public Overrides Function EndGetRequestStream (asyncResult As IAsyncResult) As Stream
参数
- asyncResult
- IAsyncResult
引用对流的挂起请求的 IAsyncResult。
返回
应用程序用于写入数据的 Stream 对象。
例外
asyncResult
为 null
。
示例
以下示例使用 EndGetRequestStream 方法结束对 Stream 对象的异步请求。
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 Class RequestDeclare
Public myFileWebRequest As FileWebRequest
Public userinput As [String]
Public Sub New()
myFileWebRequest = Nothing
End Sub
End Class
Class FileWebRequest_reqbeginend
Public Shared allDone As New ManualResetEvent(False)
' Entry point which delegates to C-style main Private Function.
Public Overloads Shared Sub Main()
Main(System.Environment.GetCommandLineArgs())
End Sub
Overloads Shared Sub Main(args() As String)
If args.Length < 2 Then
Console.WriteLine(ControlChars.Cr + "Please enter the file name as command line parameter:")
Console.WriteLine("Usage:FileWebRequest_reqbeginend <systemname>/<sharedfoldername>/<filename>")
Console.WriteLine("Example: FileWebRequest_reqbeginend shafeeque/shaf/hello.txt")
Else
Try
' Place a webrequest.
Dim myWebRequest As WebRequest = WebRequest.Create(("file://" + args(1)))
' Create an instance of the 'RequestDeclare' and associate the 'myWebRequest' to it.
Dim requestDeclare As New RequestDeclare()
requestDeclare.myFileWebRequest = CType(myWebRequest, FileWebRequest)
' 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 .
Dim r As IAsyncResult = CType(requestDeclare.myFileWebRequest.BeginGetRequestStream(AddressOf ReadCallback, requestDeclare), IAsyncResult)
allDone.WaitOne()
Console.Read()
Catch e As ProtocolViolationException
Console.WriteLine(("ProtocolViolationException is :" + e.Message))
Catch e As InvalidOperationException
Console.WriteLine(("InvalidOperationException is :" + e.Message))
Catch e As UriFormatException
Console.WriteLine(("UriFormatExceptionException is :" + e.Message))
End Try
End If
End Sub
Private Shared Sub ReadCallback(ar As IAsyncResult)
Try
' State of the request is asynchronous.
Dim requestDeclare As RequestDeclare = CType(ar.AsyncState, RequestDeclare)
Dim myFileWebRequest As FileWebRequest = requestDeclare.myFileWebRequest
Dim sendToFile As [String] = requestDeclare.userinput
' End the Asynchronus request by calling the 'EndGetRequestStream()' method.
Dim readStream As Stream = myFileWebRequest.EndGetRequestStream(ar)
' Convert the string into byte array.
Dim encoder As New ASCIIEncoding()
Dim byteArray As Byte() = encoder.GetBytes(sendToFile)
' Write to the stream.
readStream.Write(byteArray, 0, sendToFile.Length)
readStream.Close()
allDone.Set()
Console.WriteLine(ControlChars.Cr +"The String you entered was successfully written into the file.")
Console.WriteLine(ControlChars.Cr +"Press Enter to continue.")
Catch e As ApplicationException
Console.WriteLine(("ApplicationException is :" + e.Message))
End Try
End Sub
注解
方法 EndGetRequestStream 完成由 BeginGetRequestStream 方法启动的异步流请求。
注意
若要避免垃圾回收的计时问题,请务必通过在调用 方法后对 方法返回GetResponseStream的流调用 Close 方法来关闭响应流EndGetResponse。