Task<TResult>.Result 속성

정의

Task<TResult>의 결과 값을 가져옵니다.Gets the result value of this Task<TResult>.

public:
 property TResult Result { TResult get(); };
public TResult Result { get; }
member this.Result : 'Result
Public ReadOnly Property Result As TResult

속성 값

TResult

Task<TResult>작업의 형식 매개 변수와 동일한 형식인이의 결과 값입니다.The result value of this Task<TResult>, which is of the same type as the task's type parameter.

예외

작업이 취소되었습니다.The task was canceled. InnerExceptions 컬렉션에 TaskCanceledException 개체가 있습니다.The InnerExceptions collection contains a TaskCanceledException object.

또는-or- 작업을 실행하는 동안 예외가 발생한 경우An exception was thrown during the execution of the task. 예외나 예외에 대한 정보를 포함하는 InnerExceptions 컬렉션입니다.The InnerExceptions collection contains information about the exception or exceptions.

예제

다음 예제는 이름이 명령줄 인수로 전달 되는 각 디렉터리의 파일에서 바이트 수를 계산 하는 명령줄 유틸리티입니다.The following example is a command-line utility that calculates the number of bytes in the files in each directory whose name is passed as a command-line argument. 디렉터리에 파일이 포함 된 경우 FileStream 디렉터리의 각 파일에 대 한 개체를 인스턴스화하고 해당 속성의 값을 검색 하는 람다 식을 실행 합니다 FileStream.Length .If the directory contains files, it executes a lambda expression that instantiates a FileStream object for each file in the directory and retrieves the value of its FileStream.Length property. 디렉터리에 파일이 포함 되어 있지 않으면 메서드를 호출 FromResult 하 여 속성이 0 인 작업을 만듭니다 Task<TResult>.Result .If a directory contains no files, it simply calls the FromResult method to create a task whose Task<TResult>.Result property is zero (0). 태스크가 완료 되 면 모든 디렉터리 파일의 총 바이트 수를 속성에서 사용할 수 있습니다 Result .When the tasks finish, the total number of bytes in all a directory's files is available from the Result property.

using System;
using System.Collections.Generic;
using System.IO;
using System.Threading;
using System.Threading.Tasks;

public class Example
{
   public static void Main()
   {
      string[] args = Environment.GetCommandLineArgs();
      if (args.Length > 1) {
         List<Task<long>> tasks = new List<Task<long>>();
         for (int ctr = 1; ctr < args.Length; ctr++)
            tasks.Add(GetFileLengthsAsync(args[ctr]));

         try {
            Task.WaitAll(tasks.ToArray());
         }
         // Ignore exceptions here.
         catch (AggregateException) {}

         for (int ctr = 0 ; ctr < tasks.Count; ctr++) {
            if (tasks[ctr].Status == TaskStatus.Faulted)
               Console.WriteLine("{0} does not exist", args[ctr + 1]);
            else
               Console.WriteLine("{0:N0} bytes in files in '{1}'",
                                 tasks[ctr].Result, args[ctr + 1]);
         }
      }
      else {
         Console.WriteLine("Syntax error: Include one or more file paths.");
      }
   }

   private static Task<long> GetFileLengthsAsync(string filePath)
   {
      if (! Directory.Exists(filePath)) {
         return Task.FromException<long>(
                     new DirectoryNotFoundException("Invalid directory name."));
      }
      else {
         string[] files = Directory.GetFiles(filePath);
         if (files.Length == 0)
            return Task.FromResult(0L);
         else
            return Task.Run( () => { long total = 0;
                                     Parallel.ForEach(files, (fileName) => {
                                                 var fs = new FileStream(fileName, FileMode.Open,
                                                                         FileAccess.Read, FileShare.ReadWrite,
                                                                         256, true);
                                                 long length = fs.Length;
                                                 Interlocked.Add(ref total, length);
                                                 fs.Close(); } );
                                     return total;
                                   } );
      }
   }
}
// When launched with the following command line arguments:
//      subdir . newsubdir
// the example displays output like the following:
//       0 bytes in files in 'subdir'
//       2,059 bytes in files in '.'
//       newsubdir does not exist
Imports System.Collections.Generic
Imports System.IO
Imports System.Threading
Imports System.Threading.Tasks

Module Example
   Public Sub Main()
      Dim args() As String = Environment.GetCommandLineArgs()
      If args.Length > 1 Then
         Dim tasks As New List(Of Task(Of Long))
         For ctr = 1 To args.Length - 1
            tasks.Add(GetFileLengthsAsync(args(ctr)))
         Next
         Try
            Task.WaitAll(tasks.ToArray())
         ' Ignore exceptions here.
         Catch e As AggregateException
         End Try

         For ctr As Integer = 0 To tasks.Count - 1
            If tasks(ctr).Status = TaskStatus.Faulted Then
               Console.WriteLine("{0} does not exist", args(ctr + 1))
            Else
               Console.WriteLine("{0:N0} bytes in files in '{1}'",
                                 tasks(ctr).Result, args(ctr + 1))
            End If
         Next
      Else
         Console.WriteLine("Syntax error: Include one or more file paths.")
      End If
   End Sub
   
   Private Function GetFileLengthsAsync(filePath As String) As Task(Of Long)
      If Not Directory.Exists(filePath) Then
         Return Task.FromException(Of Long)(
                     New DirectoryNotFoundException("Invalid directory name."))
      Else
         Dim files As String() = Directory.GetFiles(filePath)
         If files.Length = 0 Then
            Return Task.FromResult(0L)
         Else
            Return Task.Run( Function()
                                Dim total As Long = 0
                                Dim lockObj As New Object
                                Parallel.ForEach(files, Sub(fileName)
                                                           Dim fs As New FileStream(fileName, FileMode.Open,
                                                                     FileAccess.Read, FileShare.ReadWrite,
                                                                     256, True)
                                                           Dim length As Long = fs.Length
                                                           Interlocked.Add(total, length)
                                                           fs.Close()
                                                        End Sub)
                                Return total
                             End Function )
         End If
      End If
   End Function
End Module
' When launched with the following command line arguments:
'      subdir . newsubdir
' the example displays output like the following:
'       0 bytes in files in 'subdir'
'       2,059 bytes in files in '.'
'       newsubdir does not exist

설명

속성의 get 접근자에 액세스 하면 비동기 작업이 완료 될 때까지 호출 스레드가 차단 됩니다. 메서드를 호출 하는 것과 같습니다 Wait .Accessing the property's get accessor blocks the calling thread until the asynchronous operation is complete; it is equivalent to calling the Wait method.

작업의 결과를 사용할 수 있게 되 면 저장 되 고 속성에 대 한 후속 호출에서 즉시 반환 됩니다 Result .Once the result of an operation is available, it is stored and is returned immediately on subsequent calls to the Result property. 작업을 수행 하는 동안 예외가 발생 했거나 작업이 취소 된 경우 Result 속성은 값을 반환 하지 않습니다.Note that, if an exception occurred during the operation of the task, or if the task has been cancelled, the Result property does not return a value. 대신 속성 값에 액세스 하려고 하면 AggregateException 예외가 throw 됩니다.Instead, attempting to access the property value throws an AggregateException exception.

적용 대상