使用异步/等待时防止Winforms UI阻止 [英] Prevent winforms UI block when using async/await
问题描述
我对异步/等待编程还很陌生,有时我觉得自己理解了,然后突然发生了一些事情,使我陷入了循环.
I'm fairly new to async/await programming and sometimes I feel that I understand it, and then all of a sudden something happens and throws me for a loop.
我正在测试Winforms应用程序中尝试此操作,这是我拥有的代码段的一个版本.这样做会阻塞用户界面
I'm trying this out in a test winforms app and here is one version of a snippet that I have. Doing it this way will block the UI
private async void button1_Click(object sender, EventArgs e)
{
int d = await DoStuffAsync(c);
Console.WriteLine(d);
}
private async Task<int> DoStuffAsync(CancellationTokenSource c)
{
int ret = 0;
// I wanted to simulator a long running process this way
// instead of doing Task.Delay
for (int i = 0; i < 500000000; i++)
{
ret += i;
if (i % 100000 == 0)
Console.WriteLine(i);
if (c.IsCancellationRequested)
{
return ret;
}
}
return ret;
}
现在,当我通过将"DoStuffAsync()"的主体包裹在Task中进行细微更改时,运行它就可以了.
Now, when I make a slight change by wrapping the body of "DoStuffAsync()" in a Task.Run it works perfectly fine
private async Task<int> DoStuffAsync(CancellationTokenSource c)
{
var t = await Task.Run<int>(() =>
{
int ret = 0;
for (int i = 0; i < 500000000; i++)
{
ret += i;
if (i % 100000 == 0)
Console.WriteLine(i);
if (c.IsCancellationRequested)
{
return ret;
}
}
return ret;
});
return t;
}
话虽如此,处理这种情况的正确方法是什么?
With all that said, what is the proper way to handle this scenario?
推荐答案
编写此类代码时:
private async Task<int> DoStuffAsync()
{
return 0;
}
通过这种方式,您可以同步处理事务,因为您没有使用await
表达式.
This way you are doing things synchronously, because you are not using await
expression.
请注意警告:
此异步方法缺少等待"运算符,将同步运行. 考虑使用"await"运算符来等待非阻塞API调用, 或"await Task.Run(...)"在后台线程上执行CPU绑定的工作.
This async method lacks 'await' operators and will run synchronously. Consider using the 'await' operator to await non-blocking API calls, or 'await Task.Run(...)' to do CPU-bound work on a background thread.
根据警告建议,您可以通过以下方式进行纠正:
Based on the warning suggestion you can correct it this way:
private async Task<int> DoStuffAsync()
{
return await Task.Run<int>(() =>
{
return 0;
});
}
要了解有关异步/等待的更多信息,请查看:
To learn more about async/await you can take a look at:
- 异步并等待作者:斯蒂芬·克莱里 >
- 使用Async和从msdn 等待
- Async and Await by Stephen Cleary
- Asynchronous Programming with Async and Await from msdn
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