我在使用 C# 中的新异步/等待工具时遇到问题。这是我的场景:
static async Task<bool> ManageSomeRemoteTask(int Id, bool flag)
{
var result = await serviceClient.AuthenticateIdAsync(Id);
[... Setup Some Data ...]
await serviceClient.LongAndSlowRemoteCallAsync(Data);
}
static void SendATonOfJunkToSomeWebServiceThatDoesntSupportBatches
{
var myTasks = Dictionary<int, Task<bool>>();
while(IdsLeftToProcess > 0 )
{
Task<bool> t = ManageSomeRemoteTask(Id, true);
myTasks.Add(IdsLeftToProcess ,t);
myTasks[IdsLeftToProcess].Start();
IdsLeftToProcess --;
}
Task.WaitAll(myTasks.Values.ToArray()); //Wait until they are all done
[... Report statistics ...]
}
我有 1 个问题，当我尝试运行它时，我在 Start() 上得到一个 InvalidOperationException 错误消息“Start may not be called on a promise-style task.”这个Google 或 Bing 中似乎没有出现错误消息，所以我不确定这是什么意思。这是我最关心的问题，如何让它运行。我也试过 TaskFactory.StartNew() 但不明白如何以这种方式将参数传递给我的方法。
最佳答案
异步方法返回的任务总是热，即它们是在运行状态下创建的。尝试从您的代码中删除 task.Start() - 它应该会修复它。
引自 Stephen Toub's Async/Await FAQ :
Do I need to “Start” Tasks created by methods marked as “async”?
No. Tasks returned from TAP methods are “hot”, meaning the tasks represent operations that are already in-progress. Not only do you not need to call “.Start()” on such tasks, but doing so will fail if you try. For more details, see FAQ on Task.Start.
关于c# - 在 C# 中启动许多异步任务的语法，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11236009/