c# – Page 8 – My Point of View

Use TempData or ViewBag to render HTML

This is a very basic example;

Declare this in a controller.

var fontAwesomeIcon = "<span class=\"fa fa-redo\" style=\"font-size:30px; color: red; margin-bottom: 20px; \">&nbsp;Try again</span>";

TempData["message"] = $"{fontAwesomeIcon} <h5>Something went wrong. Please try again. If problem persist, reach out to your point of contact for additional information</h5>";

And you can use it in your view;

<div class="card-body">
  <div id="divMessage">
     @Html.Raw(@TempData["message"]);
  </div>
</div>

Return values from HttpContext.Current.User.Principal and WindowsIdentity.GetCurrent()

Here is a brief explanation;

According to this forum on WindowsIdentity.GetCurrent().Name vs. User.Identity.Name:

User.Identity.Name represents the identity passed from IIS.
WindowsIdentity.GetCurrent().Name is the identity under which the thread is running.

Depending on your app’s authentication settings in IIS, they will return different values:

`Anonymous`	`Impersonate`	`User.Identity.Name`	`WindowsIndentiy.GetCurrent()`
Yes	True	`Empty String`	`IUSR_<machineName>`
Yes	False	`Empty String`	`NT Authority\Network Service`
No	True	`domain\user`	`domain\user`
No	False	`domain\user`	`NT Authority\Network Service`

Legend:

Where domain\user will show up as:
- domain\user for Active Directory
- machineName\userName for local account
Where NT Authority\Network Service will show up as:
- NT Authority\Network Service for Windows Server or ASP.NET
- machineName\ASPNET_WP for Windows XP

Resource

https://stackoverflow.com/questions/5402249/httpcontext-current-user-principal-vs-windowsidentity-getcurrent

IEnumerable vs IQueryable

The IEnumerable and IQueryable are used to hold a collection of data and also used to perform data manipulation operations such as filtering, Ordering, Grouping, etc.

The main difference is this;

We can use SQL Profiler to confirm this behavior.

All about LINQ operators

A short list of LINQ operators.

Using IN clause

This is similar to database IN keyword;

var myInClause = new string[] {"One", "Two", "Three"};

var results = from x in MyTable
              where myInClause.Contains(x.SomeColumn)
              select x;
// OR
var results = MyTable.Where(x => myInClause.Contains(x.SomeColumn));

Using ALL operator

Working with simple types

//does all numbers are greater than 10
int[] IntArray = { 11, 22, 33, 44, 55 };
var Result = IntArray.All(x => x > 10);
Console.WriteLine("Is All Numbers are greater than 10 : " + Result);

//does all names has characters greater than three
string[] stringArray = { "Khan", "Ali", "Adam", "Eve", "Joe" };
Result = stringArray.All(name => name.Length > 3);
Console.WriteLine("Is All Names are greater than 3 Characters : " + Result);

var letterResult = stringArray.All(name => name.StartsWith("A"));
Console.WriteLine("Is All Names start with letter A : " + letterResult);

//all numbers can be divided by three
int[] numbers = { 3, 6, 9, 12};
bool iSNumbersDivided = numbers.All(number => number % 3 == 0);
Console.WriteLine($"Numbers are divisible by three = {iSNumbersDivided}");

Working with complex types

//Check whether age of all animals in the zoo is greater than 1 year
bool response = animalData.All(x => x.AnimalAge > 1);
Console.WriteLine($"Is All Animals are greater than 1 years old : {response}");

//get all animas who are feed by milk
var zooSubSet = animalData.Where(x => x.Food.All(y => y.FoodType == "Milk"));
foreach(var item in zooSubSet)
{
    Console.WriteLine($"Animal Name: {item.AnimalName}");
}

Resources

https://stackoverflow.com/questions/959752/where-in-clause-in-linq

https://coderedirect.com/questions/644629/linq-nested-list-contains

Handling custom dataset in C#

I am receiving this dataset from a remote server;

TagNumber	TagCode	CageNumber	FoodType	FoodValue
A-2021-1	WHITE	A9:I10	        Milk	        A11:I
A-2021-1	WHITE	A9:I10	        Corn	        A10:I
A-2021-1	RED	A11:I13	        Meat	        B1:B2
A-2021-1	RED	A11:I13	        Hay	        A14:I
A-2021-1	GREEN	A8:J9	        Milk	        B1:B2
A-2021-1	GREEN	A8:J9	        Milk	        A10:J

I need to create this object, a complex type;

public class Animal
{
    public string TagNumber { get; set; }
    public string TagCode { get; set; }
    public string CageNumber { get; set; }
    public List<AnimalFood> Food { get; set; }
}

public class AnimalFood
{
    public string FoodType { get; set; }
    public string FoodValue { get; set; }
}

There could be many ways to handle this. This is one of them;

Create a dictionary object using LINQ GroupBy and TagCode column from incoming dataset;

var allAnimals = animalData
    .GroupBy(item => item.TagCode)
    .ToDictionary(grp => grp.Key, grp => grp.ToList());

Create unique animals out of dictionary object;

var uniqueAnimals = allAnimals.Keys.Distinct().ToList();

Create the object (animal) and add them to zoo :);

var zoo = new List<Animal>();
foreach (string animal in uniqueAnimals)
{
    var animalRow = allAnimals[animal];
    var animalRowFirst = animalRow.FirstOrDefault();
    var animalRecord = new Animal
    {
         TagNumber = animalRowFirst.TagNumber,
         TagCode = animalRowFirst.TagCode,
         CageNumber = animalRowFirst.CageNumber
    };
    //time for food
    var animalFood = new List<AnimalFood>();
    foreach(var item in animalRow)
    {
        item.Food.ForEach(x =>
        {
            animalFood.Add(new AnimalFood
            {
                  FoodType = x.FoodType,
                  FoodValue = x.FoodValue
            });
        });
    }
   //this is our custom type
   animalRecord.Food = animalFood;
   zoo.Add(animalRecord);
}

Sample output;

It’s easier to apply different filters on this object;

var animalFilter = zoo.Where(x => x.TagCode.ToUpper() == "WHITE");

Resources

https://stackoverflow.com/questions/3186818/unique-list-of-items-using-linq