ServiceStack.ServiceStackHost.OnExceptionTypeFilter C# (CSharp) Method

        public virtual void OnExceptionTypeFilter(Exception ex, ResponseStatus responseStatus)
        {
            var argEx = ex as ArgumentException;
            var isValidationSummaryEx = argEx is ValidationException;
            if (argEx != null && !isValidationSummaryEx && argEx.ParamName != null)
            {
                var paramMsgIndex = argEx.Message.LastIndexOf("Parameter name:", StringComparison.Ordinal);
                var errorMsg = paramMsgIndex > 0
                    ? argEx.Message.Substring(0, paramMsgIndex)
                    : argEx.Message;

                if (responseStatus.Errors == null)
                    responseStatus.Errors = new List<ResponseError>();

                responseStatus.Errors.Add(new ResponseError
                {
                    ErrorCode = ex.GetType().Name,
                    FieldName = argEx.ParamName,
                    Message = errorMsg,
                });
                return;
            }

            var serializationEx = ex as SerializationException;
            var errors = serializationEx?.Data["errors"] as List<RequestBindingError>;
            if (errors != null)
            {
                if (responseStatus.Errors == null)
                    responseStatus.Errors = new List<ResponseError>();

                responseStatus.Errors = errors.Select(e => new ResponseError
                {
                    ErrorCode = ex.GetType().Name,
                    FieldName = e.PropertyName,
                    Message = e.PropertyValueString != null 
                        ? $"'{e.PropertyValueString}' is an Invalid value for '{e.PropertyName}'"
                        : $"Invalid Value for '{e.PropertyName}'"
                }).ToList();
            }
        }