C# 异步 取消终止

static async Task Main(string[] args){

CancellationTokenSource cts=new CancellationTokenSource();

cts.CancelAfter(5000);//5秒之后取消操作

CancellationToken cToken=cts.Token;

await DownLoad2Async("https://www.baidu.com",200,cToken);

}

 

关键类型：CancellationToken 

static async Task Download2Async(string url,int n,CancellationToken cancellationToken){

using(HttpClient client=new HttpClient())

for(int ii=0;i<n;i++)

stirng html=await client.GetStringAsync(url);

Console.WriteLine($"{dateTime.Now}:{html}");

//方式1

if(cancellationToken.IsCancellationRequested){

Console.WriteLine("请求被取消”)

 

//方式2

cancellationToken.ThrowIfCancellationRequested();//这种方式会抛出一个异常，说明操作被取消了。

}

}