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)         


        

Answer 1

I just ran into an issue where someone was passing ex.InnerException to a method, where ex was the root. Since the parameter was also called ex it led to some confusion in the debugger when I looked at the originally caught exception. This was likely the result of some careless refactoring.

e.g.:

public void MyMethod(string input)
{
    try {
        Process(input);
    } catch (Exception ex) { // <- (2) Attempting to view ex here would show null
        _logger.log(ex);
        LogInner(ex.InnerException);
    }
}

private void LogInner(Exception ex)
{
    _logger.log(ex); // <- (1) NullReferenceExeption thrown here
    if(ex.InnerException != null)
        LogInner(ex.InnerException);
}

This was refactored as such:

public void MyMethod(string input)
{
    try {
        Process(input);
    } catch (Exception ex) {
        LogExceptionTree(ex);
    }
}

private void LogExceptionTree(Exception exception)
{
    _logger.log(exception);
    if(exception.InnerException != null)
        LogExceptionTree(exception.InnerException);
}