C# 任务结果事件已完成
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Event on Task Result is done
提问by Developer
Possible Duplicate:
How to create a task (TPL) running a STA thread?
可能的重复：
如何创建运行 STA 线程的任务 (TPL)？
I'm using the following code:
我正在使用以下代码：
var task = Task.Factory.StartNew<List<NewTwitterStatus>>(
() => GetTweets(securityKeys),
TaskCreationOptions.LongRunning);
Dispatcher.BeginInvoke(DispatcherPriority.Background,
new Action(() =>
{
var result = task.Result; // ERROR!!! The calling thread cannot access this object because a different thread owns it.
RecentTweetList.ItemsSource = result;
Visibility = result.Any() ? Visibility.Visible : Visibility.Hidden;
}));
And I'm getting the error:
我收到错误：
var result = task.Result; // ERROR!!! The calling thread cannot access this object because a different thread owns it.
What do I need to do to resolve this problem?
我需要做什么来解决这个问题？
采纳答案by Henk Holterman
The idea of Tasks is that you can chain them:
任务的想法是你可以链接它们：
var task = Task.Factory.StartNew<List<NewTwitterStatus>>(
() => GetTweets(securityKeys),
TaskCreationOptions.LongRunning
)
.ContinueWith(tsk => EndTweets(tsk) );
void EndTweets(Task<List<string>> tsk)
{
var strings = tsk.Result;
// now you have your result, Dispatchar Invoke it to the Main thread
}
回答by Trevor Pilley
You need to move the Dispatcher call into the task continuation which would look something like this:
您需要将 Dispatcher 调用移动到任务延续中，它看起来像这样：
var task = Task.Factory
.StartNew<List<NewTwitterStatus>>(() => GetTweets(securityKeys), TaskCreationOptions.LongRunning)
.ContinueWith<List<NewTwitterStatus>>(t =>
{
Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background,
new Action(() =>
{
var result = t.Result;
RecentTweetList.ItemsSource = result;
Visibility = result.Any() ? Visibility.Visible : Visibility.Hidden;
}));
},
CancellationToken.None,
TaskContinuationOptions.None);
回答by AlSki
It looks like you are starting a background task to start reading tweets, then starting another task to read the result without any co-ordination between the two.
看起来您正在启动一个后台任务来开始阅读推文，然后开始另一个任务来阅读结果，两者之间没有任何协调。
I would expect your task to have another task in a continuation (see http://msdn.microsoft.com/en-us/library/dd537609.aspx) and in the continuation you may need to invoke back to the UI thread....
我希望您的任务在延续中有另一个任务（请参阅http://msdn.microsoft.com/en-us/library/dd537609.aspx）并且在延续中您可能需要调用回 UI 线程.. ..
var getTask = Task.Factory.StartNew(...);
var analyseTask = Task.Factory.StartNew<...>(
()=>
Dispatcher.Invoke(RecentTweetList.ItemsSource = getTask.Result));
