捕获异常本身为null!

Question

我有一个ASP.NET应用程序.一切都很好,但最近我得到了自己为null的异常:

try
{
    // do something
}
catch (Exception ex)
{
    Logger.Log("Error while tried to do something. Error: " + ex.Message);
}

有时ex是null自己!

任何的想法？

Answer 1

对于在这里结束的任何人,我发现了一个可能的实例(如果只能在调试器中检测到).VS2013更新4.

破碎:

try
{
    // do something
}
catch (WebException ex) // <- both variables are named 'ex'
{
    Logger.Log("Error while tried to do something. Error: " + ex.Message);
}
catch (Exception ex) // <- this 'ex' is null
{
    Logger.Log("Error while tried to do something. Error: " + ex.Message);
}

解决方案是以不同方式命名您的异常变量.

固定:

try
{
    // do something
}
catch (WebException webEx) // <- all good in the hood
{
    Logger.Log("Error while tried to do something. Error: " + webEx.Message); // <-
}
catch (Exception ex) // <- this 'ex' correctly contains the exception
{
    Logger.Log("Error while tried to do something. Error: " + ex.Message);
}

Answer 2

在我的例子中,原因是StackOverflowException.这样的异常通常根本不会到达catch块,但这一次,由于某些原因我不明白,它确实到达了catch块,但异常是null.