BackgroundWorker.CancellationPending 속성

public:
 property bool CancellationPending { bool get(); };

public bool CancellationPending { get; }

[System.ComponentModel.Browsable(false)]
public bool CancellationPending { get; }

member this.CancellationPending : bool

[<System.ComponentModel.Browsable(false)>]
member this.CancellationPending : bool

Public ReadOnly Property CancellationPending As Boolean

속성 값

Boolean

애플리케이션에서 백그라운드 작업의 취소를 요청했으면 true이고, 그렇지 않으면 false입니다.true if the application has requested cancellation of a background operation; otherwise, false. 기본값은 false입니다.The default is false.

특성

BrowsableAttribute

예제

다음 코드 예제에서는 속성을 사용 하 여에 CancellationPending BackgroundWorker 대 한 취소 상태에 대해 쿼리 하는 방법을 보여 줍니다.The following code example demonstrates the use of the CancellationPending property to query a BackgroundWorker about its cancellation state. 이 코드 예제는에 대해 제공 된 큰 예제의 일부는 BackgroundWorker 클래스입니다.This code example is part of a larger example provided for the BackgroundWorker class.

// Abort the operation if the user has cancelled.
// Note that a call to CancelAsync may have set 
// CancellationPending to true just after the
// last invocation of this method exits, so this 
// code will not have the opportunity to set the 
// DoWorkEventArgs.Cancel flag to true. This means
// that RunWorkerCompletedEventArgs.Cancelled will
// not be set to true in your RunWorkerCompleted
// event handler. This is a race condition.
if ( worker->CancellationPending )
{
   e->Cancel = true;
}
else
{
   if ( n < 2 )
   {
      result = 1;
   }
   else
   {
      result = ComputeFibonacci( n - 1, worker, e ) + ComputeFibonacci( n - 2, worker, e );
   }

   // Report progress as a percentage of the total task.
   int percentComplete = (int)((float)n / (float)numberToCompute * 100);
   if ( percentComplete > highestPercentageReached )
   {
      highestPercentageReached = percentComplete;
      worker->ReportProgress( percentComplete );
   }
}

// Abort the operation if the user has canceled.
// Note that a call to CancelAsync may have set 
// CancellationPending to true just after the
// last invocation of this method exits, so this 
// code will not have the opportunity to set the 
// DoWorkEventArgs.Cancel flag to true. This means
// that RunWorkerCompletedEventArgs.Cancelled will
// not be set to true in your RunWorkerCompleted
// event handler. This is a race condition.

if (worker.CancellationPending)
{   
    e.Cancel = true;
}
else
{   
    if (n < 2)
    {   
        result = 1;
    }
    else
    {   
        result = ComputeFibonacci(n - 1, worker, e) + 
                 ComputeFibonacci(n - 2, worker, e);
    }

    // Report progress as a percentage of the total task.
    int percentComplete = 
        (int)((float)n / (float)numberToCompute * 100);
    if (percentComplete > highestPercentageReached)
    {
        highestPercentageReached = percentComplete;
        worker.ReportProgress(percentComplete);
    }
}

' Abort the operation if the user has canceled.
' Note that a call to CancelAsync may have set 
' CancellationPending to true just after the
' last invocation of this method exits, so this 
' code will not have the opportunity to set the 
' DoWorkEventArgs.Cancel flag to true. This means
' that RunWorkerCompletedEventArgs.Cancelled will
' not be set to true in your RunWorkerCompleted
' event handler. This is a race condition.
If worker.CancellationPending Then
    e.Cancel = True
Else
    If n < 2 Then
        result = 1
    Else
        result = ComputeFibonacci(n - 1, worker, e) + _
                 ComputeFibonacci(n - 2, worker, e)
    End If

    ' Report progress as a percentage of the total task.
    Dim percentComplete As Integer = _
        CSng(n) / CSng(numberToCompute) * 100
    If percentComplete > highestPercentageReached Then
        highestPercentageReached = percentComplete
        worker.ReportProgress(percentComplete)
    End If

End If

설명

CancellationPending가 이면 true 메서드가에서 CancelAsync 호출 된 것 BackgroundWorker 입니다.If CancellationPending is true, then the CancelAsync method has been called on the BackgroundWorker.

이 속성은 작업자 스레드에서 사용 하기 위한 것으로, CancellationPending 로 설정 된 경우 백그라운드 작업을 주기적으로 확인 하 고 중단 해야 합니다 true .This property is meant for use by the worker thread, which should periodically check CancellationPending and abort the background operation when it is set to true.

적용 대상

추가 정보

• 방법: 백그라운드에서 작업 실행How to: Run an Operation in the Background
• 방법: 백그라운드에서 파일 다운로드How to: Download a File in the Background