Best way to check for inner exception?

Question

I know sometimes innerException is null

So the following might fail:

 repEvent.InnerException = ex.InnerException.Message; 

Is ther

Answer 1

Here is another possible implementation that appends the messages and stack traces so we get them full:

private static Tuple GetFullExceptionMessageAndStackTrace(Exception exception)
{
    if (exception.InnerException == null)
    {
        if (exception.GetType() != typeof(ArgumentException))
        {
            return new Tuple(exception.Message, exception.StackTrace);
        }
        string argumentName = ((ArgumentException)exception).ParamName;
        return new Tuple(String.Format("{0} With null argument named '{1}'.", exception.Message, argumentName ), exception.StackTrace);
    }
    Tuple innerExceptionInfo = GetFullExceptionMessageAndStackTrace(exception.InnerException);
    return new Tuple(
    String.Format("{0}{1}{2}", innerExceptionInfo.Item1, Environment.NewLine, exception.Message),
    String.Format("{0}{1}{2}", innerExceptionInfo.Item2, Environment.NewLine, exception.StackTrace));
}


[Fact]
public void RecursiveExtractingOfExceptionInformationOk()
{
    // Arrange
    Exception executionException = null;
    var iExLevelTwo = new NullReferenceException("The test parameter is null");
    var iExLevelOne = new ArgumentException("Some test meesage", "myStringParamName", iExLevelTwo);
    var ex = new Exception("Some higher level message",iExLevelOne);

    // Act 
    var exMsgAndStackTrace = new Tuple("none","none");
    try
    {
        exMsgAndStackTrace = GetFullExceptionMessageAndStackTrace(ex);
    }
    catch (Exception exception)
    {
        executionException = exception;
    }

    // Assert
    Assert.Null(executionException);

    Assert.True(exMsgAndStackTrace.Item1.Contains("The test parameter is null"));
    Assert.True(exMsgAndStackTrace.Item1.Contains("Some test meesage"));
    Assert.True(exMsgAndStackTrace.Item1.Contains("Some higher level message"));
    Assert.True(exMsgAndStackTrace.Item1.Contains("myStringParamName"));

    Assert.True(!string.IsNullOrEmpty(exMsgAndStackTrace.Item2));

    Console.WriteLine(exMsgAndStackTrace.Item1);
    Console.WriteLine(exMsgAndStackTrace.Item2);
}