学步园

 

<Grid x:Name="LayoutRoot" Background="White">
<StackPanel Height="30" Orientation="Horizontal" 
                    HorizontalAlignment="Left" VerticalAlignment="Top" 
                    Margin="10" >
<Button x:Name="buttonStart" Content="Start" Click="buttonStart_Click"
                    Width="80" Height="30"/>
<Button x:Name="buttonCancel" Content="Cancel" Click="buttonCancel_Click"
                    Width="80" Height="30"/>
</StackPanel>
<StackPanel Margin="10,50,0,0" Orientation="Horizontal">
<TextBlock Text="Progress: "/>
<TextBlock x:Name="tbProgress"/>
</StackPanel>
</Grid>

 

using System.ComponentModel;
namespace BackgroundWorker
{
public partial class Page : UserControl
    {
private System.ComponentModel.BackgroundWorker bw = new System.ComponentModel.BackgroundWorker();

public Page()
        {
            InitializeComponent();

            bw.WorkerReportsProgress = true;
            bw.WorkerSupportsCancellation = true;
            bw.DoWork += new DoWorkEventHandler(bw_DoWork);
            bw.ProgressChanged += new ProgressChangedEventHandler(bw_ProgressChanged);
            bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);
        }
private void buttonStart_Click(object sender, RoutedEventArgs e)
        {
if (bw.IsBusy != true)
            {
                bw.RunWorkerAsync();
            }
        }
private void buttonCancel_Click(object sender, RoutedEventArgs e)
        {
if (bw.WorkerSupportsCancellation == true)
            {
                bw.CancelAsync();
            }
        }
private void bw_DoWork(object sender, DoWorkEventArgs e)
        {

            System.ComponentModel.BackgroundWorker worker = sender as System.ComponentModel.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));
                }
            }
        }
private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
if ((e.Cancelled == true))
            {
this.tbProgress.Text = "Canceled!";
            }

else if (!(e.Error == null))
            {
this.tbProgress.Text = ("Error: " + e.Error.Message);
            }

else
            {
this.tbProgress.Text = "Done!";
            }
        }
private void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
this.tbProgress.Text = (e.ProgressPercentage.ToString() + "%");
        }

    }
}

 

 

如果后台操作需要参数，请在调用 RunWorkerAsync 时给出参数。在 DoWork 事件处理程序内部，可以从 DoWorkEventArgs..::..Argument 属性中提取该参数。