LoggingHelper is a helper class, which will be used throughout the project to log the exception and read the complete stack trace about the exception:

    public static class LoggerHelper 
    { 
        public static string GetExceptionDetails(Exception ex) 
        { 

            StringBuilder errorString = new StringBuilder(); 
            errorString.AppendLine("An error occured. "); 
            Exception inner = ex; 
            while (inner != null) 
            { 
                errorString.Append("Error Message:"); 
                errorString.AppendLine(ex.Message); 
                errorString.Append("Stack Trace:"); 
                errorString.AppendLine(ex.StackTrace); 
                inner = inner.InnerException; 
            } 
            return errorString.ToString(); 
        } 
    }

Here is the final structure of our common layer: