c# - Caught exception is null itself !

Question

I have an ASP.NET applications. Everything was fine, but recently I get exceptions that are null themselves:

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

Sometimes ex is null itself !

Any idea?

question from:https://stackoverflow.com/questions/5634417/caught-exception-is-null-itself

Answer 1

For anyone ending up here, I've found an instance where this is possible (If only detectable in the debugger). VS2013 Update 4.

Broken:

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);
}

The solution is to name your exception variables differently.

Fixed:

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);
}