Backward Engineering a File Parsing a MicroORM Solution

Backward Engineering a File Parsing MicroORM Solution

I love my work!

I’m given application code I’ve never seen and in a language I don’t code in often enough and asked to figure it out.

Luckily, I have access to business analysts and a DBAs to get details about the business processes and databases the code is related to.

From code and info resources, create working test environment and get familiar enough with application code and databases to have new updates in to production in 2-3 weeks.

No pressure, right?

I was fairly successful today and here are some of the resources that used to solve problems I encountered.

Massive MicroORM 

It’s a small MicroORM based on the Expando or dynamic type and allows you to work with your database with almost no effort. The design is based on the idea that the code provided to you in this repository is a start: you get up and running in no-time and from there edit and alter it as you see fit.

https://github.com/FransBouma/Massive

Video: Introduction to Object-Relational Mapping (ORM)

C# Code: Checking Array Length (See if array has X elements)

Test the length

int index = 25;
if(index < array.length)
{
    //it exists
}

Source: https://stackoverflow.com/questions/794760/does-index-of-array-exist

C# ExpandoObject

C# Frequently Asked Questions:  Dynamic in C# 4.0 – Introducing the ExpandoObject
https://blogs.msdn.microsoft.com/csharpfaq/2009/09/30/dynamic-in-c-4-0-introducing-the-expandoobject/

Video: Make Apps Dynamic using the ExpandoObject

Video: How to use Massive in Master – Detail (Micro ORM – .Net – C#

Video: ASP.NET Tutorial on ADO.NET

Razor Views in C# MVC – C# Code and HTML Coexisting Together

Razor Views in C# MVC

How C# Code and HTML Coexist Together

Tonight’s study topic is Razor Views in C# MVC 5.

Here are two good resources for this topic.

Paid access to Mosh Hamedani’s Complete ASP.net MVC 5 Course. This is covered in video 16 of his course.

Also helpful, was this YouTube video that is part of a larger MVC tutorial that I really like and refer to often


VIDEO: Razor View Syntax

What are Razor Views and What Do They Do?

Specific to C# MVC, Razor Views are code snippets with special syntax made up of C# code and HTML/CSS. The C# logic can interact with and output HTML and CSS elements/attributes dynamically.

With Razor Views, we use the @ symbol to switch between C# code and HTML. 

Video: Razor Views in C# MVC

A simple example of printing numbers from 1 to 10 using Razor.

Sample Code

@for {int i = 1; i <=10; i++)
{
 <b>@i</b>
}

The Output would be: 1 2 3 4 5 6 7 8 9 10
Inside the brackets, Razor sees the <b>@i</b> and knows to render the C# variable i when its proceeded with an @ character then Razor sees the angle brackets and switches back in to HTML parsing mode.

If we didn’t want to use HTML we could change the <b> tag to <text> and output would just be text without the HTML.

The most important thing to understand and remember about Razor Views is the context switching in the parser is based on detection of specific characters.

@ character starts the C# parser but HTML & text won’t parse until Razor see a tag wrapped in angle brackets. We are just switching back and forth between to parsing modes. Make sense?

The loop is C# code but the output is HTML.
In ASP Classic and .Net, the Response Object would handle the HTML output to the browser from inside the loop.

Here are two more examples to help us cement the idea in our brains.

1. A simple date:

@{
   int day = 24;
   int month = 08;
   int year = 2020;
}
Date is @day-@month-@year

Output = Date is 24-08-2020

2. Loop thru images in folder

@for (int i = 1; i <= 5; i++)
{
  <img src="~/Images/@(i).png" />
}

Notice how in the sample above, we put the variable inside the parenthesis. Why, when we didn’t do this for the date example above?

Because if we don’t C# will try and read i. and an object with a property so we have to wrap it in parenthesis. This tell the Razor syntax that we are just trying to concatenate the values.

Razor View Code Blocks

In Razor Views we define code blocks using @{}.

@{
 int SumOfEvenNumbers = 0;
 int SumOfOddNumbers = 0;

 for(int i=1; i<=10; i++)
 {
  if(i %2==0)
  {
    SumOfEvenNumbers = SumOfEvenNumber + 1;
  }
  else
  {
    SumOfOddNumbers = SumOfOddNumbers + 1;
  }
 }
}

<h3>Sum of Even Numbers = @SumOfEvenNumbers</h3>
<h3>Sum of Odd Numbers = @SumOfOddNumbers</h3>

Razor View Comments

Razor View multi-line code comments are very similar to JavaScript and CSS that use the asterisk and forward slash, /*  */, to wrap comments.

Razor View multi-line comments use ampersand and asterisk in same way. @* to start a multi-line comment and *@ to end it. (See code example below)

What’s in the Razor View Example Below?

H2 tag class name is dynamically selected based on  logic, if Model.Customers.Count is greater than 5 then change the CSS class of the H2 element to “popular”.

Also, inside the <ul> tags, Razor View code loops through the list of customers and outputs the name.  

Sample C# Code Example:

@model  Vidly.ViewModels.RandomMovieViewModel
@{
    ViewBag.Title = "Random";
    Layout = "~/Views/Shared/_Layout.cshtml";
}
 
@*
    This is a comment
    on multiple lines

*@
 
@{
    var className = Model.Customers.Count > 5? "popular": null;
}
 
<h2 class="@className">@Model.Movie.Name</h2>
 
@if (Model.Customers.Count == 0)
{
    <text>No one has rented the movie before.</text>
}
 
else
 
{
    <ul>
        @foreach (var cusomter in Model.Customers)
        {
            <li>@cusomter.Name</li>
        }
 
    </ul>
}

For Loops for Beginners – ASP, C#, PHP, JavaScript & Python Examples

A “For Loop” executes a block of code a specific number of times or while a specified condition is true.

PHP For Loop

for (init; condition; increment)
  {
  code to be executed;
  }

php fOR lOOP PARAMETERS

  • init: Mostly used to set a counter (but can be any code to be executed once at the beginning of the loop)
  • condition: Evaluated for each loop iteration. If it evaluates to TRUE, the loop continues. If it evaluates to FALSE, the loop ends.
  • increment: Mostly used to increment a counter (but can be any code to be executed at the end of the iteration)

Note: The init and increment parameters above can be empty or have multiple expressions (separated by commas). Example The example below defines a loop that starts with i=1. The loop will continue to run as long as the variable i is less than, or equal to 5. The variable i will increase by 1 each time the loop runs:

PHP For Loop Example Code

<?php
for ($i=1; $i<=5; $i++)
  {
  echo("The number is " . $i . "<br>");
  }
?>

Classic ASP For Loop Example Code

<%
For i = 1 to 5
 Response.Write("The number is " & i & "<br>")
Next
%>

JavaScript For Loop Example

<%
For i = 1 to 5
 Response.Write("The number is " & i & "<br>")
Next
%>

C# For Loop Example

for (int i = 0; i < 5; i++) 
      {
        Console.WriteLine(i);
      }    

Python For Loop Example

states = ["Alaska", "Alabama", "Arkansas"]
for x in states:
  print(x) 
  if x == "Alabama":
    break

C# Error: The type or namespace name ‘List’ could not be found (are you missing a using directive or an assembly reference?)

OMG are your Kidding Me!

OK, I just spent an hour on this thing while trying to get started on another Tim Corey C# Developer tutorial for creating Microsoft Excel files.

When creating a custom model/object for your C# project and try to use it to build a List that made of that custom object type, you’ll be greeted with an error.

C# Error CS0246: The type or namespace name ‘List<>’ could not be found

Error: The type or namespace name ‘List’ could not be found (are you missing a using directive or an assembly reference?) 

Error seen when creating a List of custom objects without using including the using generics statement.

The missing element is a reference to using System.Collections.Generic

Code Example

using OfficeOpenXml;
using System;
using System.IO;
using System.Collections.Generic;


namespace ExcelDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            //Set the EPPlus license context to nonCommercial so we can play with it :-)
            ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
            var file = new FileInfo(@"c:\scripts\demo.xlsx");
        }

     static List<PersonModel> GetSetupData() 
        {
            List<PersonModel> output = new()
            {
                new() { Id = 1, FirstName= "rick", LastName = "cable" },
                new() { Id = 2, FirstName="bob",LastName= "marley" },
                new() { Id = 3, FirstName="willie",LastName= "nelson" }
            };

            return output;
        }
    }
}

References

As always, give credit where credit is due. In this case, a big thank you to David Morton for the post on the Microsoft Visual Studio forums.

I hope this blog post helps somebody!

Cyber Abyss!

C# Generics: Digesting Tim Corey’s C# Generics Video

C# Generics: Digesting Tim Corey’s C# Generics Video

Tonight, I’m completing a learning session on C# Generics. I’m using Tim Corey’s YouTube video on C# Generics as my tutorial.

You can get all the files to go along with Tim Corey’s C# Generics video at Time’s web site for the cost of providing Tim with your email address for his email list. You can unsubscribe anytime.

Below is Corey’s Video. Watch it, then if you’re still interested. My personal training notes will be shared below. It might help you if you’re feeling stuck or want to cement an idea in your own mind.

Tim Corey’s C# Generics Video

Re-post: C# Programming – ASCII XMas Tree w/ Code Example

This is re-post from an article I originally posted 10 years ago on 11/18/2009. I still see a bit of traffic from it so it stays on the blog.

I’m guessing the web traffic for this article is coming from programming students who have received ASCII XMas Tree as a coding project.

The original title was: Introduction to C# Programming: ASCII XMas Tree – C# and .Net Sample Project.

ORIGINAL ARTICLE

C#, pronounced C Sharp, is a relatively new programming language from Microsoft that was designed to take full advantage of the new .Net Framework.

Below is a sample project I did for a programming class I’m attending at MJC in Modesto. To test and run the code listed on this site you should download a free copy of Microsoft Visual C# Express 2005. There are four Visual Studio Express versions available for free from Microsoft, Visual Basic, C#, J# and C++.

The xmas tree project was a good idea. It really makes you think. I think this project could have been a little more fun for me if I had a little more time but my schedule just won’t allow it. I don’t see myself coming back to often to update this code but if others want to sent me some other samples I may post them later. So here it goes….

Screenshot of command line window.

C# ASCII XMas Tree Code Sample

using System;
using System.Collections.Generic;
using System.Text;
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            //create the main array
            int[] myArray = new int[] { 1, 3, 5, 7, 9 };

            //The outside foreach loop to loop throught the array
            foreach (int intLoop in myArray)
            {
                //creates the spaces, takes the array number minus 1 then divide by 2
                //this gives you the amount of spaces needed for each level of the tree
                 for (int iSpace = 0; iSpace < ((myArray[4]-intLoop)/2); iSpace++)
                {
                    System.Console.Write(" ");
                }               
                //middle loop writes the asterisks "*" the full amount of current array[]

                for (int i = 0;i < intLoop; i++)
                {               
                System.Console.Write("*");
             }
                //creates the spaces, takes the array number minus 1 then divide by 2
                //this gives you the amount of spaces needed for each level of the tree
              for (int iSpace = 0; iSpace < ((myArray[4] - intLoop) / 2); iSpace++)
             {
                 System.Console.Write(" ");
             }

            //creates new lines after all 3 loops run

             System.Console.WriteLine("");
            }
            //nest this loop and do it 3 times
            for (int iBase = 0; iBase < myArray[1]; iBase++)
            {
                // now make the base of the tree
                for (int iSpaces = 0; iSpaces < myArray[1]; iSpaces++)
                {
                    System.Console.Write(" ");
                }
                for (int iPipes = 0; iPipes < myArray[1]; iPipes++)
                {
                    System.Console.Write("|");
                }
                // now make the base of the tree
                for (int iSpaces = 0; iSpaces < myArray[1]; iSpaces++)
                {
                    System.Console.Write(" ");
                }
                  //creates new lines after all 3 loops run
                    System.Console.WriteLine("");
            }
        }
    }
}