BackgroundWorker.IsBusy Propriedade

Definição

Namespace:

System.ComponentModel

Assembly:

System.ComponentModel.EventBasedAsync.dll

Origem:

BackgroundWorker.cs

Obtém um valor que indica se o BackgroundWorker está executando uma operação assíncrona.

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

public bool IsBusy { get; }

member this.IsBusy : bool

Public ReadOnly Property IsBusy As Boolean

Valor da propriedade

Boolean

true, se o BackgroundWorker estiver executando uma operação assíncrona; caso contrário, false.

Exemplos

O exemplo de código a seguir demonstra como usar a IsBusy propriedade para aguardar a conclusão de uma BackgroundWorker operação. Este exemplo de código faz parte de um exemplo maior descrito em Como baixar um arquivo em segundo plano.

private void downloadButton_Click(object sender, EventArgs e)
{
    // Start the download operation in the background.
    this.backgroundWorker1.RunWorkerAsync();

    // Disable the button for the duration of the download.
    this.downloadButton.Enabled = false;

    // Once you have started the background thread you 
    // can exit the handler and the application will 
    // wait until the RunWorkerCompleted event is raised.

    // Or if you want to do something else in the main thread,
    // such as update a progress bar, you can do so in a loop 
    // while checking IsBusy to see if the background task is
    // still running.

    while (this.backgroundWorker1.IsBusy)
    {
        progressBar1.Increment(1);
        // Keep UI messages moving, so the form remains 
        // responsive during the asynchronous operation.
        Application.DoEvents();
    }
}

Private Sub downloadButton_Click( _
    ByVal sender As Object, _
    ByVal e As EventArgs) _
    Handles downloadButton.Click

    ' Start the download operation in the background.
    Me.backgroundWorker1.RunWorkerAsync()

    ' Disable the button for the duration of the download.
    Me.downloadButton.Enabled = False

    ' Once you have started the background thread you 
    ' can exit the handler and the application will 
    ' wait until the RunWorkerCompleted event is raised.

    ' If you want to do something else in the main thread,
    ' such as update a progress bar, you can do so in a loop 
    ' while checking IsBusy to see if the background task is
    ' still running.
    While Me.backgroundWorker1.IsBusy
        progressBar1.Increment(1)
        ' Keep UI messages moving, so the form remains 
        ' responsive during the asynchronous operation.
        Application.DoEvents()
    End While
End Sub

Comentários

O BackgroundWorker inicia uma operação assíncrona quando você chama RunWorkerAsync.

Confira também

• RunWorkerCompleted
• EventArgs
• RunWorkerAsync
• Como: Executar uma operação em segundo plano
• Como: Como baixar um arquivo em segundo plano