RunWorkerCompletedEventArgs Classe

Definição

Fornece dados para o evento MethodName Completed .Provides data for the MethodNameCompleted event.

public ref class RunWorkerCompletedEventArgs : System::ComponentModel::AsyncCompletedEventArgs
public class RunWorkerCompletedEventArgs : System.ComponentModel.AsyncCompletedEventArgs
type RunWorkerCompletedEventArgs = class
    inherit AsyncCompletedEventArgs
Public Class RunWorkerCompletedEventArgs
Inherits AsyncCompletedEventArgs
Herança
RunWorkerCompletedEventArgs

Exemplos

O exemplo de código a seguir ilustra o uso do objeto RunWorkerCompletedEventArgs.The following code example illustrates the use of RunWorkerCompletedEventArgs. Este exemplo faz parte de um exemplo maior para a BackgroundWorker classe.This example is part of a larger sample for the BackgroundWorker class.

// 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 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 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

Comentários

Ao usar o padrão assíncrono baseado em evento para operações assíncronas, um Windows Forms formulário ou controle inicia uma operação assíncrona chamando o BackgroundWorker.RunWorkerAsync método.When using the event-based asynchronous pattern for asynchronous operations, a Windows Forms form or control initiates an asynchronous operation by calling the BackgroundWorker.RunWorkerAsync method. O método, por sua vez BackgroundWorker.DoWork , gera o evento de forma assíncrona e passa a ele uma DoWorkEventArgs instância.The method in turn raises the BackgroundWorker.DoWork event asynchronously and passes it a DoWorkEventArgs instance. Se a operação assíncrona retornar um valor, o BackgroundWorker.DoWork manipulador de eventos normalmente o atribuirá à DoWorkEventArgs.Result propriedade.If the asynchronous operation returns a value, the BackgroundWorker.DoWork event handler typically assigns it to the DoWorkEventArgs.Result property. Quando a operação assíncrona é concluída, o BackgroundWorker.RunWorkerCompleted evento é gerado e passa uma RunWorkerCompletedEventArgs instância que contém informações sobre o status da operação (se ela foi cancelada, falhou ou concluída com êxito).When the asynchronous operation completes, the BackgroundWorker.RunWorkerCompleted event is raised and is passed a RunWorkerCompletedEventArgs instance that contains information about the status of the operation (whether it was cancelled, faulted, or completed successfully). Se for concluído com êxito, sua Result Propriedade conterá o valor retornado pela operação assíncrona e anteriormente atribuída à DoWorkEventArgs.Result propriedade.If it completed successfully, its Result property contains the value returned by the asynchronous operation and previously assigned to the DoWorkEventArgs.Result property.

Observação

O HostProtectionAttribute atributo aplicado a essa classe tem o seguinte Resources valor de propriedade: SharedState .The HostProtectionAttribute attribute applied to this class has the following Resources property value: SharedState. HostProtectionAttribute não afeta aplicativos de área de trabalho (que são normalmente iniciados com o clique duplo em um ícone, a digitação de um comando ou a inserção de uma URL em um navegador).The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). Para obter mais informações, consulte a HostProtectionAttribute classe ou os atributos de proteção de host e de programação de SQL Server.For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

Construtores

RunWorkerCompletedEventArgs(Object, Exception, Boolean)

Inicializa uma nova instância da classe RunWorkerCompletedEventArgs.Initializes a new instance of the RunWorkerCompletedEventArgs class.

Propriedades

Cancelled

Obtém um valor que indica se uma operação assíncrona foi cancelada.Gets a value indicating whether an asynchronous operation has been canceled.

(Herdado de AsyncCompletedEventArgs)
Error

Obtém um valor que indica qual erro ocorreu durante uma operação assíncrona.Gets a value indicating which error occurred during an asynchronous operation.

(Herdado de AsyncCompletedEventArgs)
Result

Obtém um valor que representa o resultado de uma operação assíncrona.Gets a value that represents the result of an asynchronous operation.

UserState

Obtém um valor que representa o estado do usuário.Gets a value that represents the user state.

Métodos

Equals(Object)

Determina se o objeto especificado é igual ao objeto atual.Determines whether the specified object is equal to the current object.

(Herdado de Object)
GetHashCode()

Serve como a função de hash padrão.Serves as the default hash function.

(Herdado de Object)
GetType()

Obtém o Type da instância atual.Gets the Type of the current instance.

(Herdado de Object)
MemberwiseClone()

Cria uma cópia superficial do Object atual.Creates a shallow copy of the current Object.

(Herdado de Object)
RaiseExceptionIfNecessary()

Gera uma exceção fornecida pelo usuário se uma operação assíncrona falhou.Raises a user-supplied exception if an asynchronous operation failed.

(Herdado de AsyncCompletedEventArgs)
ToString()

Retorna uma cadeia de caracteres que representa o objeto atual.Returns a string that represents the current object.

(Herdado de Object)

Aplica-se a

Confira também