WPF 精修篇 BackgroundWorker

Posted 2021-03-21 lonelyxmas

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();
        }