BASTA'21 impressions - not only c#10 features...

 
https://sharplab.io/ 

-> test c# code on the fly online

https://source.dot.net/
-> observe the source code of dot net. Deep dive into the source of dot net.

github.com

githubs1.com 
-> for alternative layout of github.com; you can also push . when browsing in github.com

https://devblogs.microsoft.com/dotnet/
-> first class microsoft blogs of ms team leaders, managers, high ranking employees

record struct Vector2d(double X, double Y)
{
    public static Vector2d operator +(Vector2d first, Vector2d second) =>
        new Vector2d(first.X + second.X, first.Y + second.Y);
}
-> like normal record but value typed (variable) and not referenced typed (pointer)
-> see         https://anthonygiretti.com/2021/08/03/introducing-c-10-record-struct/

readonly record struct
-> of course - readonly - makes record struct immutable

public string FirstName { get; init; } = "Neo";

-> c# class property set init only
-> read https://www.thomasclaudiushuber.com/2020/08/25/c-9-0-init-only-properties/

with 
var v2 = v1 with { X = 4d }; // clone v1 and override double property X with new value of 4d 
-> clones the source to modify it partially
-> see : https://docs.microsoft.com/de-de/dotnet/csharp/language-reference/operators/with-expression

Remember
4d -> 4.0 double value
4m -> 4.0 decimal value

4f -> 4.0 float value

nameof(myObject)

-> get the name description of the type

is

-> var x = "my text" is String;

-> predicate operation (true/false result) if object is of type ANY. Here is x true finally.

stackalloc

-> value types are stack allocates and not pushed to the heap

-> see https://docs.microsoft.com/de-de/dotnet/csharp/language-reference/operators/stackalloc

Span<Vector2d> vectors = stackalloc Vector2d[]
{
    new Vector2d(3d, 4d),

    new Vector2d(1d, 2d)
};
-> see https://docs.microsoft.com/de-de/dotnet/api/system.span-1?view=net-5.0

and even more....

MS SQL Merge upsert

multiple record writing - steps to achieve the fastest update of an table:

- create temp database table. This is a copy of the destination table to fill for finally.

- fille the temp database table with the bulk copy function of System.data.sqlClient.

- execute the MERGE script.

MERGE example:

MERGE [dbo].[THE_TABLE] as t

USING [dbo].[TEMP_THE_TABLE] as s

ON t.MY_ID=s.MY_ID AND t.MY_SEQUENCE=s.MY_SEQUENCE

WHEN MATCHED THEN 

UPDATE SET

        t.MY_VALUE=s.MY_VALUE,

        t.MY_TIMESTAMP=s.MY_TIMESTAMP

WHEN NOT MATCHED THEN 

INSERT (MY_ID, MY_SEQUENCE, MY_VALUE, MY_TIMESTAMP)

VALUES (s.MY_ID, s.MY_SEQUENCE, s.MY_VALUE, s.MY_TIMESTAMP);

(t=target, s=source)

Linq : short basic samples

Linq - basic how to samples:

using System.Linq;

...

[System.Serializable]
public class Item
{
public string Name;
public int ItemID;
public int Buff;
}

public class Main
{

public List<Item> Items;

public void Start()
{

string[] names = { "ralf", "Peter", "Thomas", "Christian", "Patrice" };

/* ANY demo */
var nameFound = names.Any(name => name == "Peter");
Debug.Log("Found name : " + nameFound);

/* Contains */
var nameContained = names.Contains("Christian");
Debug.Log("Found conatined : " + nameContained);

/* Distinct - remove duplicates*/
var uniqueNames = names.Distinct();

/* Where */
var result = names.Where(n => n.Length > 5);

/* select greater than results */
int[] grades = { 10, 20, 30, 40, 50, 60, 65, 70, 75, 33, 80, 13, 90, 100 };
var highGrades = grades.Where(i => i > 65);
foreach (int grade in highGrades)
{
Debug.Log("selected grade : " + grade.ToString());
}

/* select ORDER BY .. DESCENDING  */
var descGrades = grades.OrderByDescending(i => i);
foreach (var item in descGrades)
{
Debug.Log("Int item = " + item);
}

/* precondition before moving on - image the Items collection including 5x Item with various values */

/* check if ItemID 3 exists in the List of Item */
var containsId3 = Items.Where(i => i.ItemID == 3);
var itemId3found = Items.Any(i=>i.ItemID == 3);
Debug.Log("is Items including ItemId 3 : " + itemId3found);

/* select all items with buff greater then 60 and print them out */
var itemsGT60 = Items.Where(i => i.Buff > 60);
foreach (var buff in itemsGT60)
{
Debug.Log("buff Items > 60 : " + buff);
}

/* calculate the average of all the buff stats */
var resultAverage = Items.Average(i => i.Buff);
Debug.Log("Average : " + resultAverage);
}

}

...

// find the entry in an array of objects where each object got the property 'Name'

using System;

string searchForName = "Patrice"

var foundItem = Array.Find(CollectionOfItems, x=> x.Name==searchForName);

json - newtowsoft - JArray - SelectToken

how to fill JArray and select all and specific items? 

private Newtonsoft.Json.Linq.JArray UFOS = new jsonlib.Linq.JArray();

dynamic json = Newtonsoft.Json.JsonConvert.DeserializeObject(myUFOjsonSourceString);

var list = json.list; // List of UFO items - 'list' is the root element of the source JSON structure

foreach (var item in list)
{
..
UFOS.Add(item);
...
}

IEnumerable<jsonlib.Linq.JToken> allUFOS= UFOS.SelectToken("$"); // okay, all UFOs

IEnumerable<jsonlib.Linq.JToken> oneUFO = UFOS.SelectToken("$[?(@.Pilot=='E.T.')]"); // okay, if each item of UFO would contain the property 'Pilot', select the one where Pilot=E.T. (you know, this small odd alien who wants to get home again)

Sample II:

Parse XML using Newtonsoft.Json

<root>
  <light>
    <color>red</color>
    <intensity>bright</intensity>
  </light>
  <light>
    <color>green</color>
    <intensity>light</intensity>
  </light>
</root>

XDocument doc = XDocument.Parse(mySampleXmlString); //or XDocument.Load(path)
string jsonText = JsonConvert.SerializeXNode(doc);
dynamic pseudoXml = JsonConvert.DeserializeObject(jsonText);
Newtonsoft.Json.Linq.JArray lights = (Newtonsoft.Json.Linq.JArray)pseudoXml["root"]["light"];
foreach (var light in lights)
{
    string color = (string)light.color;
    string intensity = (string)light.intensity;
}

Pass string parameter plus optional placeholder fill up arguments to a method - method signature for String.Format(..)

how to setup a method getting args to be applied using String.Format(....)?

Example:

        private void log(object text, params object[] param)
        {
            string line;
            if (param != null && param.Length > 0)
                line = String.Format(text.ToString(), param);
            else
                line = text.ToString();
            if (Environment.UserInteractive==true)
                Console.WriteLine(line);
        }

text to enum value

classic request how to convert a text entry to an enum value? See..

Colors orange = (Colors) Enum.Parse(typeof(Colors), "Red, Yellow");

how to get the current assembly version

            var assembly = Assembly.GetExecutingAssembly();
            string version = assembly.GetName().Version.ToString();