WPF 精修篇 BackgroundWorker

原文:WPF 精修篇 BackgroundWorker

效果

   <Grid>





        <Grid.RowDefinitions>





            <RowDefinition Height="22*"/>





            <RowDefinition Height="11*"/>





            <RowDefinition Height="47*"/>





        </Grid.RowDefinitions>





        <StackPanel Orientation="Horizontal" Margin="0,28" VerticalAlignment="Center">





            <Label>开始数据</Label>





            <TextBox x:Name="beginText" HorizontalAlignment="Left" Height="31" TextWrapping="Wrap" Text="100" VerticalAlignment="Top" Width="100"/>





            <Label>结束数据</Label>





            <TextBox x:Name="endText" HorizontalAlignment="Left" Height="31" TextWrapping="Wrap" Text="1000000000" VerticalAlignment="Top" Width="100"/>





            <Button x:Name="button" Content="开始" HorizontalAlignment="Center" VerticalAlignment="Center" Width="75" Click="Button_Click"/>





            <Button x:Name="Cancel" Content="取消" HorizontalAlignment="Center" VerticalAlignment="Center" Width="75" Click="Cancel_Click"/>





        </StackPanel>





        <StackPanel Margin="0" Grid.Row="1" Grid.RowSpan="2">





            <TextBlock x:Name="odd" TextWrapping="Wrap"  Text="奇数数量："/>





            <TextBlock x:Name="even" TextWrapping="Wrap" Text="偶数数量："/>





            <ProgressBar x:Name="Prebar" Height="20"/>





        </StackPanel>





    </Grid>

      private int oddcount =0;





        private int evencount =0;





        public void Make(int from ,int to)





        {





            oddcount = 0;





            evencount = 0;





            int num = (to - from) / 100;





            for (int i = from; i < to; i++)





            {





                if (worker.CancellationPending == true) 





                {





                    return;





                }





              





                if (i % 2 == 0)





                {





                    evencount++;





                }





                else 





                {





                    oddcount++;





                }





                if (i % num == 0 && (worker != null) && (worker.WorkerReportsProgress = true)) 





                {





                    worker.ReportProgress(i / num);





                }





            }





           





        }





        BackgroundWorker worker = null;





        private void Button_Click(object sender, RoutedEventArgs e)





        {   





            int from=0;





            int to = 0;





            if(int.TryParse(beginText.Text,out from)&&int.TryParse(endText.Text,out to) )





            {





                button.IsEnabled = false;





                            odd.Text = "奇数数量：0" ;





                           even.Text = "偶数数量：0" ;





 





                  worker = new BackgroundWorker();





                //异步取消 需要增加这个 不然取消失效





                  worker.WorkerSupportsCancellation = true;





                //支持报告进度





                  worker.WorkerReportsProgress = true;





                //注册滚动条事件





                worker.ProgressChanged+=worker_ProgressChanged;





               





                //注册任务





                  worker.DoWork+=worker_DoWork;





                  //任务完毕触发





                  worker.RunWorkerCompleted += worker_RunWorkerCompleted;





                //给任务传参





                  worker.RunWorkerAsync(new Tuple<int, int>(from, to));





 





            }





 





        }





 





        private void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)





        {





            Prebar.Value = e.ProgressPercentage;





        }





 





        void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)





        {





          //  throw new NotImplementedException();





            if (sender is BackgroundWorker) 





            {





 





                if (e.Cancelled == true)





                {





                    odd.Text = "任务已取消";





                    even.Text = "";





                }





                else 





                {





                    odd.Text = "奇数数量：" + oddcount;





                    even.Text = "偶数数量：" + evencount;





                }





                BackgroundWorker k = (BackgroundWorker)sender;





                k.DoWork -= worker_DoWork;





                k.RunWorkerCompleted -= worker_RunWorkerCompleted;





                k = null;





                button.IsEnabled = true;





            }





       





        }





 





        private void worker_DoWork(object sender, DoWorkEventArgs e)





        {





            var args = ( Tuple<int, int>)e.Argument;





            Make(args.Item1, args.Item2);





            if (worker.CancellationPending == true) 





            {





                e.Cancel = true;





            }





        }





 





         





        private void Cancel_Click(object sender, RoutedEventArgs e)





        {





 





            worker.CancelAsync();





        }