在 C# 中重新引发异常的正确方法是什么?

问题描述

这样做更好吗:

try
{
    ...
}
catch (Exception ex)
{
    ...
    throw;
}

或者这个:

try
{
    ...
}
catch (Exception ex)
{
    ...
    throw ex;
}

他们做同样的事情吗?一个比另一个好?

Do they do the same thing? Is one better than the other?

推荐答案

您应该始终使用以下语法重新引发异常.否则你会踩到堆栈跟踪:

You should always use the following syntax to rethrow an exception. Else you'll stomp the stack trace:

throw;

如果您打印由 throw ex 产生的跟踪，您会看到它以该语句结束，而不是异常的真正来源.

If you print the trace resulting from throw ex, you'll see that it ends on that statement and not at the real source of the exception.

基本上，使用throw ex应该被视为刑事犯罪.

Basically, it should be deemed a criminal offense to use throw ex.

如果需要重新抛出来自其他地方(AggregateException、TargetInvocationException)或可能来自另一个线程的异常，您也不应该直接重新抛出它.而是有 ExceptionDispatchInfo 保留所有必要的信息.

If there is a need to rethrow an exception that comes from somewhere else (AggregateException, TargetInvocationException) or perhaps another thread, you also shouldn't rethrow it directly. Rather there is the ExceptionDispatchInfo that preserves all the necessary information.

try
{
    methodInfo.Invoke(...);
}
catch (System.Reflection.TargetInvocationException e)
{
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture(e.InnerException).Throw();
    throw; // just to inform the compiler that the flow never leaves the block
}