c# - 如何在我的主应用程序线程中自动捕获由 Task 对象的操作抛出的异常？

Question

我注意到 DispatcherUnhandledException 事件处理程序没有捕捉到从我的主应用程序线程以外的线程抛出的异常。所以我必须像这样手动抛出它们:

Task.Factory.StartNew(() =>
{
    throw new Exception("oops! something went wrong...");

}).ContinueWith((task) =>
{
    if (task.IsFaulted)
    {
        App.Current.Dispatcher.Invoke(new Action(() =>
        {
            throw task.Exception.InnerExceptions.First();
        }));
    }
});

但是，我不想将上述 ContinueWith 方法添加到我创建的每个任务中。我宁愿有一些方法可以自动处理这个问题。

Answer 1

下面的类解决了这个问题:

/// <summary>
/// Extends the System.Threading.Tasks.Task by automatically throwing the first exception to the main application thread.
/// </summary>
public class TaskEx
{
    public Task Task { get; private set; }

    private TaskEx(Action action)
    {
        Task = Task.Factory.StartNew(action).ContinueWith((task) =>
        {
            ThrowTaskException(task);
        });
    }

    public static TaskEx StartNew(Action action)
    {
        if (action == null)
        {
            throw new ArgumentNullException();
        }

        return new TaskEx(action);
    }

    public TaskEx ContinueWith(Action<Task> continuationAction)
    {
        if (continuationAction == null)
        {
            throw new ArgumentNullException();
        }

        Task = Task.ContinueWith(continuationAction).ContinueWith((task) =>
        {
            ThrowTaskException(task);
        });

        return this;
    }

    private void ThrowTaskException(Task task)
    {
        if (task.IsFaulted)
        {
            App.Current.Dispatcher.Invoke(new Action(() =>
            {
                throw task.Exception.InnerExceptions.First();
            }));
        }
    }
}

现在我可以简单地使用以下代码(与 Task 类完全相同):

TaskEx.StartNew(() =>
{
    // do something that may cause an exception
}).ContinueWith((task) =>
{
    // then do something else that may cause an exception
}).ContinueWith((task) =>
{
    // then do yet something else that may cause an exception
});

然而，与 Task 类不同的是，从这些线程之一抛出的任何异常都将被我的 DispatcherUnhandledException 事件处理程序自动捕获。