Catching exceptions caused in different threads [duplicate]

问题

The below example is a simplification of my problem. An exception is thrown within a new thread. If im not handling this within the thread it is not caught by the outer try/catch and crashes my application.

Is there any way to guarantee that I catch any exception that occurs.

        try
        {
            new Thread(delegate()
                {
                    throw new Exception("Bleh"); // <--- This is not caught

                }).Start();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }

回答1:

Generally speaking, it's easiest to catch the exceptions within the thread itself.

But if you want to catch the exception separately from the thread function itself (and if you can use Task instead of the old Thread approach), you can write code like this:

var task = Task.Factory.StartNew(() =>
{
    throw new Exception("Test");
});

task.ContinueWith(t => handleException(t.Exception), TaskContinuationOptions.OnlyOnFaulted);

This uses ContinueWith() to call another method after the first thread has finished and an exception occurred, so you can log the exception or whatever:

static void handleException(AggregateException exception)
{
    foreach (var ex in exception.Flatten().InnerExceptions)
        Console.WriteLine(ex.Message);
}

This doesn't really let you fix anything up - the only sensible way to do that is to handle the exceptions properly in the thread function itself.

回答2:

I put it this way, and I believe this is the safest:

 var thread =   new Thread(MyMethod);
 thread.start();

This the method. The try-catch should be inside any thread-method

 private void MyMethod()
 {
    try
    {
        {
            throw new Exception("Bleh");//<--- This's not caught => now it is caught :)
        }
    }
    catch (Exception ex)
    {
        Logger.Log(ex.ToString());
    }
}

回答3:

Use AppDomain.UnhandledException, Application.ThreadException or Dispatcher.UnhandledException. It depends on the actual type of application.

Another possibility is to use AOP (PostSharp comes to mind). However, catching exceptions is not not the one and only goal. You need to find a way to fix the cause of the exception. If it is a bug, the exception is helpful and logging sufficient. If there is a more sophisticated reason you need to think about it and apply countermeasures. Unfortunately, there's no "general solution". So if you are'nt catching exceptions beforehand, I doubt you can act on it well.

回答4:

In my understanding .Net does not allow communicating between two threads. Beacause threads are isolated from one another. You can acheive this in a simple way and i don't know how much it will fit for you. Please mark the answer if it useful.

public  Exception exception;

private void button1_Click(object sender, EventArgs e)
{
        try
        {
            new Thread(delegate()
            {
                try
                {
                    throw new Exception("Bleh"); // <--- This is not caught
                }
                catch (Exception e)
                {
                    exception = e;
                }

            }).Start();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }

        if (exception != null)
        {
            //your code here
        }

    }

来源：https://stackoverflow.com/questions/17298269/catching-exceptions-caused-in-different-threads

标签

multithreading

exception-handling

thread-safety