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();
}

原文地址：https://www.cnblogs.com/lonelyxmas/p/12075538.html