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AggregateException.Flatten 方法在 MSDN 上的文档说明如下：“如果任何内部异常本身是 AggregateException 的实例，则此方法将递归地展平所有异常。新 AggregateException 中返回的内部异常将是所有根植于提供的 AggregateException 实例的异常树的内部异常。”

这听起来很可疑，就像我们将丢失堆栈跟踪信息一样，所以我查看了Reference Source上的实现，看起来堆栈跟踪信息确实会丢失。

所以我们进行了测试：

try
{
    try
    {
        try
        {
            throw new InvalidOperationException();
        }
        catch (Exception e)
        {
            try
            {
                throw new FormatException();
            }
            catch (Exception e2)
            {
                throw new AggregateException(e, e2);
            }
        }
    }
    catch (Exception e)
    {
        try
        {
            throw new NotImplementedException();
        }
        catch (Exception e2)
        {
            throw new AggregateException(e, e2);
        }
    }
}
catch (Exception e)
{
    File.AppendAllText(@"C:\tmp.txt", e.ToString());
    File.AppendAllText(@"C:\tmp.txt", ((AggregateException)e).Flatten().ToString());
}

测试的输出如下：

System.AggregateException: One or more errors occurred. ---> System.AggregateException: One or more errors occurred. ---> System.InvalidOperationException: Operation is not valid due to the current state of the object.
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 29
   --- End of inner exception stack trace ---
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 39
   --- End of inner exception stack trace ---
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 51
---> (Inner Exception #0) System.AggregateException: One or more errors occurred. ---> System.InvalidOperationException: Operation is not valid due to the current state of the object.
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 29
   --- End of inner exception stack trace ---
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 39
---> (Inner Exception #0) System.InvalidOperationException: Operation is not valid due to the current state of the object.
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 29<---

---> (Inner Exception #1) System.FormatException: One of the identified items was in an invalid format.
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 35<---
<---

---> (Inner Exception #1) System.NotImplementedException: The method or operation is not implemented.
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 47<---
System.AggregateException: One or more errors occurred. ---> System.NotImplementedException: The method or operation is not implemented.
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 47
   --- End of inner exception stack trace ---
---> (Inner Exception #0) System.NotImplementedException: The method or operation is not implemented.
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 47<---

---> (Inner Exception #1) System.InvalidOperationException: Operation is not valid due to the current state of the object.
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 29<---

---> (Inner Exception #2) System.FormatException: One of the identified items was in an invalid format.
   at ConsoleApplication6.Program.Main(String[] args) in C:\Projects\ConsoleApplication6\ConsoleApplication6\Program.cs:line 35<---

请注意，扁平化的 AggregateException 中没有提到第 39 行！！！

这个丢失的信息重要吗？或者，当我们展平 AggregateException 时，我们是否会丢失第 39 行并不重要？

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1 回答 1

1

如果我正确理解了您的示例，那么您是说在引发 AggregateException 时创建的堆栈跟踪丢失了。这是意料之中的，因为 Flatten() 将过滤掉任何属于 InnerExceptions 层次结构的 AggregateExceptions。我不会说信息丢失了，因为在大多数情况下有用的信息将在非 AggregateException 实例中。

于 2015-10-26T12:27:22.653 回答