让我们以一点点诚实开始吧.我不是goto的粉丝,但我也不是一遍又一遍地重复我的代码的粉丝.无论如何,我遇到了这种情况.这是不寻常的,但不是出于这个世界.我不禁想知道这是否适合goto.有没有更好的办法？
public Task Process(CancellationTokenSource token)
{
await SpinUpServiceAsync();
foreach (var item in LongList())
{
if (token.IsCancellationRequested) goto cancel;
await LongTask1(item);
if (token.IsCancellationRequested) goto cancel;
await LongTask2(item);
if (token.IsCancellationRequested) goto cancel;
await LongTask3(item);
if (token.IsCancellationRequested) goto cancel;
await LongTask4(item);
if (token.IsCancellationRequested) goto cancel;
await LongTask5(item);
continue;
cancel:
{
Log($"Cancelled during {item}");
await SpinDownServiceAsync();
return;
}
}
}
这是我看到的下一个最佳选择：
public Task Process(CancellationTokenSource token)
{
await SpinUpServiceAsync();
foreach (var item in LongList())
{
if (token.IsCancellationRequested)
{
Log($"Cancelled during {item}");
await SpinDownServiceAsync();
return;
}
await LongTask1(item);
if (token.IsCancellationRequested)
{
Log($"Cancelled during {item}");
await SpinDownServiceAsync();
return;
}
await LongTask2(item);
if (token.IsCancellationRequested)
{
Log($"Cancelled during {item}");
await SpinDownServiceAsync();
return;
}
await LongTask3(item);
if (token.IsCancellationRequested)
{
Log($"Cancelled during {item}");
await SpinDownServiceAsync();
return;
}
await LongTask4(item);
if (token.IsCancellationRequested)
{
Log($"Cancelled during {item}");
await SpinDownServiceAsync();
return;
}
await LongTask5(item);
}
}
但看看那不必要的重复.
谢谢你的考虑.
解决方法
我没有LongTask1-5的确切类型,但我会这样做.
public Task Process(CancellationTokenSource token)
{
SOMETYPE[] tasks = new SOMETYPE[] {LongTask1,LongTask2,LongTask3,LongTask4,LongTask5};
await SpinUpServiceAsync();
foreach (var item in LongList())
{
foreach(var task in tasks){
if (token.IsCancellationRequested) {
Log($"Cancelled during {item}");
await SpinDownServiceAsync();
return;
}
await task(item);
}
}
}
这种方法将任务放在一个数组中.如果需求发生变化,需要更多任务,那么数组定义会变长,但其余代码保持不变.好的代码使用循环来执行重复性任务,而不是像原始帖子中那样的大量复制和粘贴.
