BackgroundWorker Class

Definition

별도의 스레드에서 작업을 실행합니다.Executes an operation on a separate thread.

public ref class BackgroundWorker : IDisposable
public ref class BackgroundWorker : System::ComponentModel::Component
public class BackgroundWorker : IDisposable
public class BackgroundWorker : System.ComponentModel.Component
type BackgroundWorker = class
    interface IDisposable
type BackgroundWorker = class
    inherit Component
Public Class BackgroundWorker
Implements IDisposable
Public Class BackgroundWorker
Inherits Component
Inheritance
BackgroundWorker
Inheritance

Examples

다음 코드 예제에서는 시간이 많이 걸리는 작업을 비동기적으로 실행 하기 위한 BackgroundWorker 클래스의 기본 사항을 보여 줍니다.The following code example demonstrates the basics of the BackgroundWorker class for executing a time-consuming operation asynchronously. 다음 그림에서는 출력의 예를 보여 줍니다.The following illustration shows an example of the output.

BackgroundWorker simple 예제BackgroundWorker simple example

이 코드를 실행 하려면 Windows Forms 애플리케이션을 작성 합니다.To try this code, create a Windows Forms application. resultLabel 이라는 Label 컨트롤을 추가 하 고 startAsyncButtoncancelAsyncButton라는 두 개의 Button 컨트롤을 추가 합니다.Add a Label control named resultLabel and add two Button controls named startAsyncButton and cancelAsyncButton. 두 단추에 대 한 Click 이벤트 처리기를 만듭니다.Create Click event handlers for both buttons. 도구 상자의 구성 요소 탭에서 backgroundWorker1이라는 BackgroundWorker 구성 요소를 추가 합니다.From the Components tab of the Toolbox, add a BackgroundWorker component named backgroundWorker1. BackgroundWorker에 대 한 DoWork, ProgressChangedRunWorkerCompleted 이벤트 처리기를 만듭니다.Create DoWork, ProgressChanged, and RunWorkerCompleted event handlers for the BackgroundWorker. 폼의 코드에서 기존 코드를 다음 코드로 바꿉니다.In the code for the form, replace the existing code with the following code.

using System;
using System.ComponentModel;
using System.Windows.Forms;

namespace BackgroundWorkerSimple
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            backgroundWorker1.WorkerReportsProgress = true;
            backgroundWorker1.WorkerSupportsCancellation = true;
        }

        private void startAsyncButton_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.IsBusy != true)
            {
                // Start the asynchronous operation.
                backgroundWorker1.RunWorkerAsync();
            }
        }

        private void cancelAsyncButton_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.WorkerSupportsCancellation == true)
            {
                // Cancel the asynchronous operation.
                backgroundWorker1.CancelAsync();
            }
        }

        // This event handler is where the time-consuming work is done.
        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker worker = sender as BackgroundWorker;

            for (int i = 1; i <= 10; i++)
            {
                if (worker.CancellationPending == true)
                {
                    e.Cancel = true;
                    break;
                }
                else
                {
                    // Perform a time consuming operation and report progress.
                    System.Threading.Thread.Sleep(500);
                    worker.ReportProgress(i * 10);
                }
            }
        }

        // This event handler updates the progress.
        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            resultLabel.Text = (e.ProgressPercentage.ToString() + "%");
        }

        // This event handler deals with the results of the background operation.
        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Cancelled == true)
            {
                resultLabel.Text = "Canceled!";
            }
            else if (e.Error != null)
            {
                resultLabel.Text = "Error: " + e.Error.Message;
            }
            else
            {
                resultLabel.Text = "Done!";
            }
        }
    }
}
Imports System.ComponentModel

Public Class Form1

    Public Sub New()
        InitializeComponent()
        backgroundWorker1.WorkerReportsProgress = True
        backgroundWorker1.WorkerSupportsCancellation = True
    End Sub

    Private Sub startAsyncButton_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles startAsyncButton.Click
        If backgroundWorker1.IsBusy <> True Then
            ' Start the asynchronous operation.
            backgroundWorker1.RunWorkerAsync()
        End If
    End Sub

    Private Sub cancelAsyncButton_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles cancelAsyncButton.Click
        If backgroundWorker1.WorkerSupportsCancellation = True Then
            ' Cancel the asynchronous operation.
            backgroundWorker1.CancelAsync()
        End If
    End Sub

    ' This event handler is where the time-consuming work is done.
    Private Sub backgroundWorker1_DoWork(ByVal sender As System.Object, _
    ByVal e As DoWorkEventArgs) Handles backgroundWorker1.DoWork
        Dim worker As BackgroundWorker = CType(sender, BackgroundWorker)
        Dim i As Integer

        For i = 1 To 10
            If (worker.CancellationPending = True) Then
                e.Cancel = True
                Exit For
            Else
                ' Perform a time consuming operation and report progress.
                System.Threading.Thread.Sleep(500)
                worker.ReportProgress(i * 10)
            End If
        Next
    End Sub

    ' This event handler updates the progress.
    Private Sub backgroundWorker1_ProgressChanged(ByVal sender As System.Object, _
    ByVal e As ProgressChangedEventArgs) Handles backgroundWorker1.ProgressChanged
        resultLabel.Text = (e.ProgressPercentage.ToString() + "%")
    End Sub

    ' This event handler deals with the results of the background operation.
    Private Sub backgroundWorker1_RunWorkerCompleted(ByVal sender As System.Object, _
    ByVal e As RunWorkerCompletedEventArgs) Handles backgroundWorker1.RunWorkerCompleted
        If e.Cancelled = True Then
            resultLabel.Text = "Canceled!"
        ElseIf e.Error IsNot Nothing Then
            resultLabel.Text = "Error: " & e.Error.Message
        Else
            resultLabel.Text = "Done!"
        End If
    End Sub
End Class

다음 코드 예제에서는 시간이 많이 걸리는 작업을 비동기적으로 실행 하기 위해 BackgroundWorker 클래스를 사용 하는 방법을 보여 줍니다.The following code example demonstrates the use of the BackgroundWorker class for executing a time-consuming operation asynchronously. 다음 그림에서는 출력의 예를 보여 줍니다.The following illustration shows an example of the output.

BackgroundWorker 피보나치 예제BackgroundWorker Fibonacci example

작업 선택한 피보나치 수를 계산 하 고 계산 진행 되 면 진행률 업데이트를 보고 취소할 보류 중인 계산을 허용 합니다.The operation computes the selected Fibonacci number, reports progress updates as the calculation proceeds, and permits a pending calculation to be canceled.

#using <System.Drawing.dll>
#using <System.dll>
#using <System.Windows.Forms.dll>

using namespace System;
using namespace System::Collections;
using namespace System::ComponentModel;
using namespace System::Drawing;
using namespace System::Threading;
using namespace System::Windows::Forms;

public ref class FibonacciForm: public System::Windows::Forms::Form
{
private:

   int numberToCompute;
   int highestPercentageReached;

   System::Windows::Forms::NumericUpDown^ numericUpDown1;
   System::Windows::Forms::Button^ startAsyncButton;
   System::Windows::Forms::Button^ cancelAsyncButton;
   System::Windows::Forms::ProgressBar^ progressBar1;
   System::Windows::Forms::Label ^ resultLabel;
   System::ComponentModel::BackgroundWorker^ backgroundWorker1;

public:
   FibonacciForm()
   {
      InitializeComponent();
      numberToCompute = highestPercentageReached = 0;
      InitializeBackgoundWorker();
   }


private:

   // Set up the BackgroundWorker object by 
   // attaching event handlers. 
   void InitializeBackgoundWorker()
   {
      backgroundWorker1->DoWork += gcnew DoWorkEventHandler( this, &FibonacciForm::backgroundWorker1_DoWork );
      backgroundWorker1->RunWorkerCompleted += gcnew RunWorkerCompletedEventHandler( this, &FibonacciForm::backgroundWorker1_RunWorkerCompleted );
      backgroundWorker1->ProgressChanged += gcnew ProgressChangedEventHandler( this, &FibonacciForm::backgroundWorker1_ProgressChanged );
   }

   void startAsyncButton_Click( System::Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      
      // Reset the text in the result label.
      resultLabel->Text = String::Empty;

      // Disable the UpDown control until 
      // the asynchronous operation is done.
      this->numericUpDown1->Enabled = false;

      // Disable the Start button until 
      // the asynchronous operation is done.
      this->startAsyncButton->Enabled = false;

      // Enable the Cancel button while 
      // the asynchronous operation runs.
      this->cancelAsyncButton->Enabled = true;

      // Get the value from the UpDown control.
      numberToCompute = (int)numericUpDown1->Value;

      // Reset the variable for percentage tracking.
      highestPercentageReached = 0;

      // Start the asynchronous operation.
      backgroundWorker1->RunWorkerAsync( numberToCompute );
   }

   void cancelAsyncButton_Click( System::Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {  
      // Cancel the asynchronous operation.
      this->backgroundWorker1->CancelAsync();
      
      // Disable the Cancel button.
      cancelAsyncButton->Enabled = false;
   }

   // This event handler is where the actual,
   // potentially time-consuming work is done.
   void backgroundWorker1_DoWork( Object^ sender, DoWorkEventArgs^ e )
   {
      // Get the BackgroundWorker that raised this event.
      BackgroundWorker^ worker = dynamic_cast<BackgroundWorker^>(sender);

      // Assign the result of the computation
      // to the Result property of the DoWorkEventArgs
      // object. This is will be available to the 
      // RunWorkerCompleted eventhandler.
      e->Result = ComputeFibonacci( safe_cast<Int32>(e->Argument), worker, e );
   }

   // This event handler deals with the results of the
   // background operation.
   void backgroundWorker1_RunWorkerCompleted( Object^ /*sender*/, RunWorkerCompletedEventArgs^ e )
   {
      // First, handle the case where an exception was thrown.
      if ( e->Error != nullptr )
      {
         MessageBox::Show( e->Error->Message );
      }
      else
      if ( e->Cancelled )
      {
         // Next, handle the case where the user cancelled 
         // the operation.
         // Note that due to a race condition in 
         // the DoWork event handler, the Cancelled
         // flag may not have been set, even though
         // CancelAsync was called.
         resultLabel->Text = "Cancelled";
      }
      else
      {
         // Finally, handle the case where the operation 
         // succeeded.
         resultLabel->Text = e->Result->ToString();
      }

      // Enable the UpDown control.
      this->numericUpDown1->Enabled = true;

      // Enable the Start button.
      startAsyncButton->Enabled = true;

      // Disable the Cancel button.
      cancelAsyncButton->Enabled = false;
   }

   // This event handler updates the progress bar.
   void backgroundWorker1_ProgressChanged( Object^ /*sender*/, ProgressChangedEventArgs^ e )
   {
      this->progressBar1->Value = e->ProgressPercentage;
   }

   // This is the method that does the actual work. For this
   // example, it computes a Fibonacci number and
   // reports progress as it does its work.
   long ComputeFibonacci( int n, BackgroundWorker^ worker, DoWorkEventArgs ^ e )
   {
      // The parameter n must be >= 0 and <= 91.
      // Fib(n), with n > 91, overflows a long.
      if ( (n < 0) || (n > 91) )
      {
         throw gcnew ArgumentException( "value must be >= 0 and <= 91","n" );
      }

      long result = 0;
      
      // 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 );
         }
      }

      return result;
   }

   void InitializeComponent()
   {
      this->numericUpDown1 = gcnew System::Windows::Forms::NumericUpDown;
      this->startAsyncButton = gcnew System::Windows::Forms::Button;
      this->cancelAsyncButton = gcnew System::Windows::Forms::Button;
      this->resultLabel = gcnew System::Windows::Forms::Label;
      this->progressBar1 = gcnew System::Windows::Forms::ProgressBar;
      this->backgroundWorker1 = gcnew System::ComponentModel::BackgroundWorker;
      (dynamic_cast<System::ComponentModel::ISupportInitialize^>(this->numericUpDown1))->BeginInit();
      this->SuspendLayout();
      
      // 
      // numericUpDown1
      // 
      this->numericUpDown1->Location = System::Drawing::Point( 16, 16 );
      array<Int32>^temp0 = {91,0,0,0};
      this->numericUpDown1->Maximum = System::Decimal( temp0 );
      array<Int32>^temp1 = {1,0,0,0};
      this->numericUpDown1->Minimum = System::Decimal( temp1 );
      this->numericUpDown1->Name = "numericUpDown1";
      this->numericUpDown1->Size = System::Drawing::Size( 80, 20 );
      this->numericUpDown1->TabIndex = 0;
      array<Int32>^temp2 = {1,0,0,0};
      this->numericUpDown1->Value = System::Decimal( temp2 );

      // 
      // startAsyncButton
      // 
      this->startAsyncButton->Location = System::Drawing::Point( 16, 72 );
      this->startAsyncButton->Name = "startAsyncButton";
      this->startAsyncButton->Size = System::Drawing::Size( 120, 23 );
      this->startAsyncButton->TabIndex = 1;
      this->startAsyncButton->Text = "Start Async";
      this->startAsyncButton->Click += gcnew System::EventHandler( this, &FibonacciForm::startAsyncButton_Click );

      // 
      // cancelAsyncButton
      // 
      this->cancelAsyncButton->Enabled = false;
      this->cancelAsyncButton->Location = System::Drawing::Point( 153, 72 );
      this->cancelAsyncButton->Name = "cancelAsyncButton";
      this->cancelAsyncButton->Size = System::Drawing::Size( 119, 23 );
      this->cancelAsyncButton->TabIndex = 2;
      this->cancelAsyncButton->Text = "Cancel Async";
      this->cancelAsyncButton->Click += gcnew System::EventHandler( this, &FibonacciForm::cancelAsyncButton_Click );

      // 
      // resultLabel
      // 
      this->resultLabel->BorderStyle = System::Windows::Forms::BorderStyle::Fixed3D;
      this->resultLabel->Location = System::Drawing::Point( 112, 16 );
      this->resultLabel->Name = "resultLabel";
      this->resultLabel->Size = System::Drawing::Size( 160, 23 );
      this->resultLabel->TabIndex = 3;
      this->resultLabel->Text = "(no result)";
      this->resultLabel->TextAlign = System::Drawing::ContentAlignment::MiddleCenter;

      // 
      // progressBar1
      // 
      this->progressBar1->Location = System::Drawing::Point( 18, 48 );
      this->progressBar1->Name = "progressBar1";
      this->progressBar1->Size = System::Drawing::Size( 256, 8 );
      this->progressBar1->Step = 2;
      this->progressBar1->TabIndex = 4;

      // 
      // backgroundWorker1
      // 
      this->backgroundWorker1->WorkerReportsProgress = true;
      this->backgroundWorker1->WorkerSupportsCancellation = true;

      // 
      // FibonacciForm
      // 
      this->ClientSize = System::Drawing::Size( 292, 118 );
      this->Controls->Add( this->progressBar1 );
      this->Controls->Add( this->resultLabel );
      this->Controls->Add( this->cancelAsyncButton );
      this->Controls->Add( this->startAsyncButton );
      this->Controls->Add( this->numericUpDown1 );
      this->Name = "FibonacciForm";
      this->Text = "Fibonacci Calculator";
      (dynamic_cast<System::ComponentModel::ISupportInitialize^>(this->numericUpDown1))->EndInit();
      this->ResumeLayout( false );
   }
};

[STAThread]
int main()
{
   Application::Run( gcnew FibonacciForm );
}
using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Threading;
using System.Windows.Forms;

namespace BackgroundWorkerExample
{	
    public class FibonacciForm : System.Windows.Forms.Form
    {	
        private int numberToCompute = 0;
        private int highestPercentageReached = 0;

        private System.Windows.Forms.NumericUpDown numericUpDown1;
        private System.Windows.Forms.Button startAsyncButton;
        private System.Windows.Forms.Button cancelAsyncButton;
        private System.Windows.Forms.ProgressBar progressBar1;
        private System.Windows.Forms.Label resultLabel;
        private System.ComponentModel.BackgroundWorker backgroundWorker1;

        public FibonacciForm()
        {	
            InitializeComponent();

            InitializeBackgroundWorker();
        }

        // Set up the BackgroundWorker object by 
        // attaching event handlers. 
        private void InitializeBackgroundWorker()
        {
            backgroundWorker1.DoWork += 
                new DoWorkEventHandler(backgroundWorker1_DoWork);
            backgroundWorker1.RunWorkerCompleted += 
                new RunWorkerCompletedEventHandler(
            backgroundWorker1_RunWorkerCompleted);
            backgroundWorker1.ProgressChanged += 
                new ProgressChangedEventHandler(
            backgroundWorker1_ProgressChanged);
        }
    
        private void startAsyncButton_Click(System.Object sender, 
            System.EventArgs e)
        {
            // Reset the text in the result label.
            resultLabel.Text = String.Empty;

            // Disable the UpDown control until 
            // the asynchronous operation is done.
            this.numericUpDown1.Enabled = false;

            // Disable the Start button until 
            // the asynchronous operation is done.
            this.startAsyncButton.Enabled = false;

            // Enable the Cancel button while 
            // the asynchronous operation runs.
            this.cancelAsyncButton.Enabled = true;

            // Get the value from the UpDown control.
            numberToCompute = (int)numericUpDown1.Value;

            // Reset the variable for percentage tracking.
            highestPercentageReached = 0;

            // Start the asynchronous operation.
            backgroundWorker1.RunWorkerAsync(numberToCompute);
        }

        private void cancelAsyncButton_Click(System.Object sender, 
            System.EventArgs e)
        {   
            // Cancel the asynchronous operation.
            this.backgroundWorker1.CancelAsync();

            // Disable the Cancel button.
            cancelAsyncButton.Enabled = false;
        }

        // This event handler is where the actual,
        // potentially time-consuming work is done.
        private void backgroundWorker1_DoWork(object sender, 
            DoWorkEventArgs e)
        {   
            // Get the BackgroundWorker that raised this event.
            BackgroundWorker worker = sender as BackgroundWorker;

            // Assign the result of the computation
            // to the Result property of the DoWorkEventArgs
            // object. This is will be available to the 
            // RunWorkerCompleted eventhandler.
            e.Result = ComputeFibonacci((int)e.Argument, worker, e);
        }

        // This event handler deals with the results of the
        // background operation.
        private void backgroundWorker1_RunWorkerCompleted(
            object sender, RunWorkerCompletedEventArgs e)
        {
            // First, handle the case where an exception was thrown.
            if (e.Error != null)
            {
                MessageBox.Show(e.Error.Message);
            }
            else if (e.Cancelled)
            {
                // Next, handle the case where the user canceled 
                // the operation.
                // Note that due to a race condition in 
                // the DoWork event handler, the Cancelled
                // flag may not have been set, even though
                // CancelAsync was called.
                resultLabel.Text = "Canceled";
            }
            else
            {
                // Finally, handle the case where the operation 
                // succeeded.
                resultLabel.Text = e.Result.ToString();
            }

            // Enable the UpDown control.
            this.numericUpDown1.Enabled = true;

            // Enable the Start button.
            startAsyncButton.Enabled = true;

            // Disable the Cancel button.
            cancelAsyncButton.Enabled = false;
        }

        // This event handler updates the progress bar.
        private void backgroundWorker1_ProgressChanged(object sender,
            ProgressChangedEventArgs e)
        {
            this.progressBar1.Value = e.ProgressPercentage;
        }

        // This is the method that does the actual work. For this
        // example, it computes a Fibonacci number and
        // reports progress as it does its work.
        long ComputeFibonacci(int n, BackgroundWorker worker, DoWorkEventArgs e)
        {
            // The parameter n must be >= 0 and <= 91.
            // Fib(n), with n > 91, overflows a long.
            if ((n < 0) || (n > 91))
            {
                throw new ArgumentException(
                    "value must be >= 0 and <= 91", "n");
            }

            long result = 0;

            // 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);
                }
            }

            return result;
        }

        #region Windows Form Designer generated code
        
        private void InitializeComponent()
        {
            this.numericUpDown1 = new System.Windows.Forms.NumericUpDown();
            this.startAsyncButton = new System.Windows.Forms.Button();
            this.cancelAsyncButton = new System.Windows.Forms.Button();
            this.resultLabel = new System.Windows.Forms.Label();
            this.progressBar1 = new System.Windows.Forms.ProgressBar();
            this.backgroundWorker1 = new System.ComponentModel.BackgroundWorker();
            ((System.ComponentModel.ISupportInitialize)(this.numericUpDown1)).BeginInit();
            this.SuspendLayout();
            // 
            // numericUpDown1
            // 
            this.numericUpDown1.Location = new System.Drawing.Point(16, 16);
            this.numericUpDown1.Maximum = new System.Decimal(new int[] {
            91,
            0,
            0,
            0});
            this.numericUpDown1.Minimum = new System.Decimal(new int[] {
            1,
            0,
            0,
            0});
            this.numericUpDown1.Name = "numericUpDown1";
            this.numericUpDown1.Size = new System.Drawing.Size(80, 20);
            this.numericUpDown1.TabIndex = 0;
            this.numericUpDown1.Value = new System.Decimal(new int[] {
            1,
            0,
            0,
            0});
            // 
            // startAsyncButton
            // 
            this.startAsyncButton.Location = new System.Drawing.Point(16, 72);
            this.startAsyncButton.Name = "startAsyncButton";
            this.startAsyncButton.Size = new System.Drawing.Size(120, 23);
            this.startAsyncButton.TabIndex = 1;
            this.startAsyncButton.Text = "Start Async";
            this.startAsyncButton.Click += new System.EventHandler(this.startAsyncButton_Click);
            // 
            // cancelAsyncButton
            // 
            this.cancelAsyncButton.Enabled = false;
            this.cancelAsyncButton.Location = new System.Drawing.Point(153, 72);
            this.cancelAsyncButton.Name = "cancelAsyncButton";
            this.cancelAsyncButton.Size = new System.Drawing.Size(119, 23);
            this.cancelAsyncButton.TabIndex = 2;
            this.cancelAsyncButton.Text = "Cancel Async";
            this.cancelAsyncButton.Click += new System.EventHandler(this.cancelAsyncButton_Click);
            // 
            // resultLabel
            // 
            this.resultLabel.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
            this.resultLabel.Location = new System.Drawing.Point(112, 16);
            this.resultLabel.Name = "resultLabel";
            this.resultLabel.Size = new System.Drawing.Size(160, 23);
            this.resultLabel.TabIndex = 3;
            this.resultLabel.Text = "(no result)";
            this.resultLabel.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
            // 
            // progressBar1
            // 
            this.progressBar1.Location = new System.Drawing.Point(18, 48);
            this.progressBar1.Name = "progressBar1";
            this.progressBar1.Size = new System.Drawing.Size(256, 8);
            this.progressBar1.Step = 2;
            this.progressBar1.TabIndex = 4;
            // 
            // backgroundWorker1
            // 
            this.backgroundWorker1.WorkerReportsProgress = true;
            this.backgroundWorker1.WorkerSupportsCancellation = true;
            // 
            // FibonacciForm
            // 
            this.ClientSize = new System.Drawing.Size(292, 118);
            this.Controls.Add(this.progressBar1);
            this.Controls.Add(this.resultLabel);
            this.Controls.Add(this.cancelAsyncButton);
            this.Controls.Add(this.startAsyncButton);
            this.Controls.Add(this.numericUpDown1);
            this.Name = "FibonacciForm";
            this.Text = "Fibonacci Calculator";
            ((System.ComponentModel.ISupportInitialize)(this.numericUpDown1)).EndInit();
            this.ResumeLayout(false);
        }
        #endregion

        [STAThread]
        static void Main()
        {
            Application.Run(new FibonacciForm());
        }
    }
}
Imports System.Collections
Imports System.ComponentModel
Imports System.Drawing
Imports System.Threading
Imports System.Windows.Forms

Public Class FibonacciForm
    Inherits System.Windows.Forms.Form

    Private numberToCompute As Integer = 0
    Private highestPercentageReached As Integer = 0

    Private numericUpDown1 As System.Windows.Forms.NumericUpDown
    Private WithEvents startAsyncButton As System.Windows.Forms.Button
    Private WithEvents cancelAsyncButton As System.Windows.Forms.Button
    Private progressBar1 As System.Windows.Forms.ProgressBar
    Private resultLabel As System.Windows.Forms.Label
    Private WithEvents backgroundWorker1 As System.ComponentModel.BackgroundWorker


    Public Sub New()
        InitializeComponent()
    End Sub

    Private Sub startAsyncButton_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) _
    Handles startAsyncButton.Click

        ' Reset the text in the result label.
        resultLabel.Text = [String].Empty

        ' Disable the UpDown control until 
        ' the asynchronous operation is done.
        Me.numericUpDown1.Enabled = False

        ' Disable the Start button until 
        ' the asynchronous operation is done.
        Me.startAsyncButton.Enabled = False

        ' Enable the Cancel button while 
        ' the asynchronous operation runs.
        Me.cancelAsyncButton.Enabled = True

        ' Get the value from the UpDown control.
        numberToCompute = CInt(numericUpDown1.Value)

        ' Reset the variable for percentage tracking.
        highestPercentageReached = 0


        ' Start the asynchronous operation.
        backgroundWorker1.RunWorkerAsync(numberToCompute)
    End Sub 

    Private Sub cancelAsyncButton_Click( _
    ByVal sender As System.Object, _
    ByVal e As System.EventArgs) _
    Handles cancelAsyncButton.Click
        
        ' Cancel the asynchronous operation.
        Me.backgroundWorker1.CancelAsync()

        ' Disable the Cancel button.
        cancelAsyncButton.Enabled = False
        
    End Sub

    ' This event handler is where the actual work is done.
    Private Sub backgroundWorker1_DoWork( _
    ByVal sender As Object, _
    ByVal e As DoWorkEventArgs) _
    Handles backgroundWorker1.DoWork

        ' Get the BackgroundWorker object that raised this event.
        Dim worker As BackgroundWorker = _
            CType(sender, BackgroundWorker)

        ' Assign the result of the computation
        ' to the Result property of the DoWorkEventArgs
        ' object. This is will be available to the 
        ' RunWorkerCompleted eventhandler.
        e.Result = ComputeFibonacci(e.Argument, worker, e)
    End Sub

    ' This event handler deals with the results of the
    ' background operation.
    Private Sub backgroundWorker1_RunWorkerCompleted( _
    ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs) _
    Handles backgroundWorker1.RunWorkerCompleted

        ' First, handle the case where an exception was thrown.
        If (e.Error IsNot Nothing) Then
            MessageBox.Show(e.Error.Message)
        ElseIf e.Cancelled Then
            ' Next, handle the case where the user canceled the 
            ' operation.
            ' Note that due to a race condition in 
            ' the DoWork event handler, the Cancelled
            ' flag may not have been set, even though
            ' CancelAsync was called.
            resultLabel.Text = "Canceled"
        Else
            ' Finally, handle the case where the operation succeeded.
            resultLabel.Text = e.Result.ToString()
        End If

        ' Enable the UpDown control.
        Me.numericUpDown1.Enabled = True

        ' Enable the Start button.
        startAsyncButton.Enabled = True

        ' Disable the Cancel button.
        cancelAsyncButton.Enabled = False
    End Sub

    ' This event handler updates the progress bar.
    Private Sub backgroundWorker1_ProgressChanged( _
    ByVal sender As Object, ByVal e As ProgressChangedEventArgs) _
    Handles backgroundWorker1.ProgressChanged

        Me.progressBar1.Value = e.ProgressPercentage

    End Sub

    ' This is the method that does the actual work. For this
    ' example, it computes a Fibonacci number and
    ' reports progress as it does its work.
    Function ComputeFibonacci( _
        ByVal n As Integer, _
        ByVal worker As BackgroundWorker, _
        ByVal e As DoWorkEventArgs) As Long

        ' The parameter n must be >= 0 and <= 91.
        ' Fib(n), with n > 91, overflows a long.
        If n < 0 OrElse n > 91 Then
            Throw New ArgumentException( _
                "value must be >= 0 and <= 91", "n")
        End If

        Dim result As Long = 0

        ' 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

        Return result

    End Function


    Private Sub InitializeComponent()
        Me.numericUpDown1 = New System.Windows.Forms.NumericUpDown
        Me.startAsyncButton = New System.Windows.Forms.Button
        Me.cancelAsyncButton = New System.Windows.Forms.Button
        Me.resultLabel = New System.Windows.Forms.Label
        Me.progressBar1 = New System.Windows.Forms.ProgressBar
        Me.backgroundWorker1 = New System.ComponentModel.BackgroundWorker
        CType(Me.numericUpDown1, System.ComponentModel.ISupportInitialize).BeginInit()
        Me.SuspendLayout()
        '
        'numericUpDown1
        '
        Me.numericUpDown1.Location = New System.Drawing.Point(16, 16)
        Me.numericUpDown1.Maximum = New Decimal(New Integer() {91, 0, 0, 0})
        Me.numericUpDown1.Minimum = New Decimal(New Integer() {1, 0, 0, 0})
        Me.numericUpDown1.Name = "numericUpDown1"
        Me.numericUpDown1.Size = New System.Drawing.Size(80, 20)
        Me.numericUpDown1.TabIndex = 0
        Me.numericUpDown1.Value = New Decimal(New Integer() {1, 0, 0, 0})
        '
        'startAsyncButton
        '
        Me.startAsyncButton.Location = New System.Drawing.Point(16, 72)
        Me.startAsyncButton.Name = "startAsyncButton"
        Me.startAsyncButton.Size = New System.Drawing.Size(120, 23)
        Me.startAsyncButton.TabIndex = 1
        Me.startAsyncButton.Text = "Start Async"
        '
        'cancelAsyncButton
        '
        Me.cancelAsyncButton.Enabled = False
        Me.cancelAsyncButton.Location = New System.Drawing.Point(153, 72)
        Me.cancelAsyncButton.Name = "cancelAsyncButton"
        Me.cancelAsyncButton.Size = New System.Drawing.Size(119, 23)
        Me.cancelAsyncButton.TabIndex = 2
        Me.cancelAsyncButton.Text = "Cancel Async"
        '
        'resultLabel
        '
        Me.resultLabel.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D
        Me.resultLabel.Location = New System.Drawing.Point(112, 16)
        Me.resultLabel.Name = "resultLabel"
        Me.resultLabel.Size = New System.Drawing.Size(160, 23)
        Me.resultLabel.TabIndex = 3
        Me.resultLabel.Text = "(no result)"
        Me.resultLabel.TextAlign = System.Drawing.ContentAlignment.MiddleCenter
        '
        'progressBar1
        '
        Me.progressBar1.Location = New System.Drawing.Point(18, 48)
        Me.progressBar1.Name = "progressBar1"
        Me.progressBar1.Size = New System.Drawing.Size(256, 8)
        Me.progressBar1.TabIndex = 4
        '
        'backgroundWorker1
        '
        Me.backgroundWorker1.WorkerReportsProgress = True
        Me.backgroundWorker1.WorkerSupportsCancellation = True
        '
        'FibonacciForm
        '
        Me.ClientSize = New System.Drawing.Size(292, 118)
        Me.Controls.Add(Me.progressBar1)
        Me.Controls.Add(Me.resultLabel)
        Me.Controls.Add(Me.cancelAsyncButton)
        Me.Controls.Add(Me.startAsyncButton)
        Me.Controls.Add(Me.numericUpDown1)
        Me.Name = "FibonacciForm"
        Me.Text = "Fibonacci Calculator"
        CType(Me.numericUpDown1, System.ComponentModel.ISupportInitialize).EndInit()
        Me.ResumeLayout(False)

    End Sub

    <STAThread()> _
    Shared Sub Main()
        Application.Run(New FibonacciForm)
    End Sub
End Class

Remarks

BackgroundWorker 클래스를 사용 하면 별도의 전용 스레드에서 작업을 실행할 수 있습니다.The BackgroundWorker class allows you to run an operation on a separate, dedicated thread. 다운로드 및 데이터베이스 트랜잭션과 같은 시간이 많이 걸리는 작업은 사용자 인터페이스 (UI) 실행 하 고 응답을 멈춘 것 처럼 보일 수 발생할 수 있습니다.Time-consuming operations like downloads and database transactions can cause your user interface (UI) to seem as though it has stopped responding while they are running. 응답성이 뛰어난 UI를 원할 때 이러한 작업과 관련 된 긴 지연이 발생 하는 경우 BackgroundWorker 클래스는 편리한 솔루션을 제공 합니다.When you want a responsive UI and you are faced with long delays associated with such operations, the BackgroundWorker class provides a convenient solution.

백그라운드에서 시간이 많이 걸리는 작업을 실행 하려면 BackgroundWorker를 만들고 작업의 진행률을 보고 하는 이벤트를 수신 하 고 작업이 완료 되 면 신호를 수신 합니다.To execute a time-consuming operation in the background, create a BackgroundWorker and listen for events that report the progress of your operation and signal when your operation is finished. BackgroundWorker를 프로그래밍 방식으로 만들거나 도구 상자구성 요소 탭에서 폼으로 끌어올 수 있습니다.You can create the BackgroundWorker programmatically or you can drag it onto your form from the Components tab of the Toolbox. Windows Forms 디자이너에서 BackgroundWorker를 만들면 구성 요소 트레이에 표시 되 고 해당 속성이 속성 창에 표시 됩니다.If you create the BackgroundWorker in the Windows Forms Designer, it will appear in the Component Tray, and its properties will be displayed in the Properties window.

백그라운드 작업을 설정 하려면 DoWork 이벤트에 대 한 이벤트 처리기를 추가 합니다.To set up for a background operation, add an event handler for the DoWork event. 이 이벤트 처리기에서 시간이 오래 걸리는 작업을 호출 합니다.Call your time-consuming operation in this event handler. 작업을 시작 하려면 RunWorkerAsync를 호출 합니다.To start the operation, call RunWorkerAsync. 진행률 업데이트에 대 한 알림을 받으려면 ProgressChanged 이벤트를 처리 합니다.To receive notifications of progress updates, handle the ProgressChanged event. 작업이 완료 될 때 알림을 받으려면 RunWorkerCompleted 이벤트를 처리 합니다.To receive a notification when the operation is completed, handle the RunWorkerCompleted event.

Note

DoWork 이벤트 처리기에서 사용자 인터페이스 개체를 조작 하지 않도록 주의 해야 합니다.You must be careful not to manipulate any user-interface objects in your DoWork event handler. 대신 ProgressChangedRunWorkerCompleted 이벤트를 통해 사용자 인터페이스와 통신 합니다.Instead, communicate to the user interface through the ProgressChanged and RunWorkerCompleted events.

BackgroundWorker 이벤트는 AppDomain 경계를 넘어 마샬링되지 않습니다.BackgroundWorker events are not marshaled across AppDomain boundaries. BackgroundWorker 구성 요소를 사용 하 여 둘 이상의 AppDomain에서 다중 스레드 작업을 수행 하지 마십시오.Do not use a BackgroundWorker component to perform multithreaded operations in more than one AppDomain.

백그라운드 작업에 매개 변수가 필요한 경우 매개 변수를 사용 하 여 RunWorkerAsync를 호출 합니다.If your background operation requires a parameter, call RunWorkerAsync with your parameter. DoWork 이벤트 처리기 내에서 DoWorkEventArgs.Argument 속성의 매개 변수를 추출할 수 있습니다.Inside the DoWork event handler, you can extract the parameter from the DoWorkEventArgs.Argument property.

BackgroundWorker에 대한 자세한 내용은 방법: 백그라운드에서 작업 실행을 참조하세요.For more information about BackgroundWorker, see How to: Run an Operation in the Background.

Constructors

BackgroundWorker() BackgroundWorker 클래스의 새 인스턴스를 초기화합니다.Initializes a new instance of the BackgroundWorker class.

Properties

CancellationPending

응용 프로그램에서 백그라운드 작업의 취소를 요청 하는지 여부를 나타내는 값을 가져옵니다.Gets a value indicating whether the application has requested cancellation of a background operation.

CanRaiseEvents

구성 요소 이벤트를 발생 시킬 수 있는지 여부를 나타내는 값을 가져옵니다.Gets a value indicating whether the component can raise an event.

(Inherited from Component)
Container

IContainer을 포함하는 Component를 가져옵니다.Gets the IContainer that contains the Component.

(Inherited from Component)
DesignMode

Component가 현재 디자인 모드인지 여부를 나타내는 값을 가져옵니다.Gets a value that indicates whether the Component is currently in design mode.

(Inherited from Component)
Events

Component에 연결된 이벤트 처리기의 목록을 가져옵니다.Gets the list of event handlers that are attached to this Component.

(Inherited from Component)
IsBusy

BackgroundWorker가 비동기 작업을 실행하고 있는지 여부를 나타내는 값을 가져옵니다.Gets a value indicating whether the BackgroundWorker is running an asynchronous operation.

Site

ComponentISite를 가져오거나 설정합니다.Gets or sets the ISite of the Component.

(Inherited from Component)
WorkerReportsProgress

BackgroundWorker가 진행률 업데이트를 보고할 수 있는지 여부를 나타내는 값을 가져오거나 설정합니다.Gets or sets a value indicating whether the BackgroundWorker can report progress updates.

WorkerSupportsCancellation

BackgroundWorker가 비동기 취소를 지원하는지 여부를 나타내는 값을 가져오거나 설정합니다.Gets or sets a value indicating whether the BackgroundWorker supports asynchronous cancellation.

Methods

CancelAsync()

보류 중인 백그라운드 작업의 취소를 요청 합니다.Requests cancellation of a pending background operation.

CreateObjRef(Type)

원격 개체와 통신 하는 데 프록시를 생성 하는 데 필요한 모든 관련 정보를 포함 하는 개체를 만듭니다.Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.

(Inherited from MarshalByRefObject)
Dispose()
Dispose() Component에서 사용한 모든 리소스를 해제합니다.Releases all resources used by the Component. (Inherited from Component)
Dispose(Boolean)
Dispose(Boolean) Component에서 사용한 관리되지 않는 리소스를 해제하고 선택적으로 관리되는 리소스를 해제합니다.Releases the unmanaged resources used by the Component and optionally releases the managed resources. (Inherited from Component)
Equals(Object)

지정한 개체와 현재 개체가 같은지 여부를 확인합니다.Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode()

기본 해시 함수로 작동합니다.Serves as the default hash function.

(Inherited from Object)
GetLifetimeService()

이 인스턴스의 수명 정책을 제어 하는 현재의 수명 서비스 개체를 검색 합니다.Retrieves the current lifetime service object that controls the lifetime policy for this instance.

(Inherited from MarshalByRefObject)
GetService(Type)

Component 또는 해당 Container에서 제공하는 서비스를 나타내는 개체를 반환합니다.Returns an object that represents a service provided by the Component or by its Container.

(Inherited from Component)
GetType()

현재 인스턴스의 Type을 가져옵니다.Gets the Type of the current instance.

(Inherited from Object)
InitializeLifetimeService()

이 인스턴스의 수명 정책을 제어하는 수명 서비스 개체를 가져옵니다.Obtains a lifetime service object to control the lifetime policy for this instance.

(Inherited from MarshalByRefObject)
MemberwiseClone()

현재 Object의 단순 복사본을 만듭니다.Creates a shallow copy of the current Object.

(Inherited from Object)
MemberwiseClone(Boolean)

현재 MarshalByRefObject 개체의 단순 복사본을 만듭니다.Creates a shallow copy of the current MarshalByRefObject object.

(Inherited from MarshalByRefObject)
OnDoWork(DoWorkEventArgs) DoWork 이벤트를 발생시킵니다.Raises the DoWork event.
OnProgressChanged(ProgressChangedEventArgs) ProgressChanged 이벤트를 발생시킵니다.Raises the ProgressChanged event.
OnRunWorkerCompleted(RunWorkerCompletedEventArgs) RunWorkerCompleted 이벤트를 발생시킵니다.Raises the RunWorkerCompleted event.
ReportProgress(Int32) ProgressChanged 이벤트를 발생시킵니다.Raises the ProgressChanged event.
ReportProgress(Int32, Object) ProgressChanged 이벤트를 발생시킵니다.Raises the ProgressChanged event.
RunWorkerAsync()

백그라운드 작업의 실행을 시작합니다.Starts execution of a background operation.

RunWorkerAsync(Object)

백그라운드 작업의 실행을 시작합니다.Starts execution of a background operation.

ToString()

현재 개체를 나타내는 문자열을 반환합니다.Returns a string that represents the current object.

(Inherited from Object)
ToString()

Component의 이름이 포함된 String을 반환합니다(있는 경우).Returns a String containing the name of the Component, if any. 이 메서드는 재정의할 수 없습니다.This method should not be overridden.

(Inherited from Component)

Events

Disposed

Dispose() 메서드를 호출하여 구성 요소를 삭제할 때 발생합니다.Occurs when the component is disposed by a call to the Dispose() method.

(Inherited from Component)
DoWork

RunWorkerAsync()가 호출될 때 발생합니다.Occurs when RunWorkerAsync() is called.

ProgressChanged

ReportProgress(Int32)가 호출될 때 발생합니다.Occurs when ReportProgress(Int32) is called.

RunWorkerCompleted

백그라운드 작업이 완료 또는 취소 되었거나 예외가 발생 하는 경우 발생 합니다.Occurs when the background operation has completed, has been canceled, or has raised an exception.

Applies to

See also