Tag: csharp

Ignoring SSL certificate errors in C# RestSharp Library

- by mahmood 
//bypass ssl validation check by using RestClient object
var options = new RestClientOptions(baseurl) {
    RemoteCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true;
};
var restClient = new RestClient(options);

or in application level

//bypass ssl validation check globally for whole application.
ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => true;

 

Ignoring SSL certificate errors in C# HttpClient

- by mahmood 
var handler = new HttpClientHandler();
handler.ClientCertificateOptions = ClientCertificateOption.Manual;
handler.ServerCertificateCustomValidationCallback = 
    (httpRequestMessage, cert, cetChain, policyErrors) =>
{
    return true;
};

var client = new HttpClient(handler);

 

C# Generics

- by mahmood

C# allows you to define generic classes, interfaces, abstract classes, fields, methods, static methods, properties, events, delegates, and operators using the type parameter and without the specific data type. A type parameter is a placeholder for a particular type specified when creating an instance of the generic type.

Generic Class

class DataStore<T>
{
    public T Data { get; set; }
}

You can also define multiple type parameters separated by a comma.

class KeyValuePair<TKey, TValue>
{
    public TKey Key { get; set; }
    public TValue Value { get; set; }
}

Instantiating Generic Class

DataStore<string> store = new DataStore<string>();

DataStore<string> store = new DataStore<string>();
store.Data = "Hello World!";
//store.Data = 123; //compile-time error

You can specify the different data types for different objects, as shown below.

DataStore<string> strStore = new DataStore<string>();
strStore.Data = "Hello World!";
//strStore.Data = 123; // compile-time error

DataStore<int> intStore = new DataStore<int>();
intStore.Data = 100;
//intStore.Data = "Hello World!"; // compile-time error

KeyValuePair<int, string> kvp1 = new KeyValuePair<int, string>();
kvp1.Key = 100;
kvp1.Value = "Hundred";

KeyValuePair<string, string> kvp2 = new KeyValuePair<string, string>();
kvp2.Key = "IT";
kvp2.Value = "Information Technology";

Generic Fields

class DataStore<T>
{
    public T data;
}
class DataStore<T>
{
    public T[] data = new T[10];
}

Generic Methods

class DataStore<T>
{
    private T[] _data = new T[10];
    
    public void AddOrUpdate(int index, T item)
    {
        if(index >= 0 && index < 10)
            _data[index] = item;
    }

    public T GetData(int index)
    {
        if(index >= 0 && index < 10)
            return _data[index];
        else 
            return default(T);
    }
}
DataStore<string> cities = new DataStore<string>();
cities.AddOrUpdate(0, "Mumbai");
cities.AddOrUpdate(1, "Chicago");
cities.AddOrUpdate(2, "London");

DataStore<int> empIds = new DataStore<int>();
empIds.AddOrUpdate(0, 50);
empIds.AddOrUpdate(1, 65);
empIds.AddOrUpdate(2, 89);
class Printer
{
    public void Print<T>(T data)
    {
        Console.WriteLine(data);
    }
}

Printer printer = new Printer();
printer.Print<int>(100);
printer.Print(200); // type infer from the specified value
printer.Print<string>("Hello");
printer.Print("World!"); // type infer from the specified value

References
https://www.tutorialsteacher.com/csharp/csharp-generics
https://learn.microsoft.com/en-us/dotnet/csharp/fundamentals/types/generics

Raw string literals in C# 11

- by mahmood

Raw string literals can contain arbitrary text, including whitespace, new lines, embedded quotes, and other special characters without requiring escape sequences.

string longMessage = """
    This is a long message.
    It has several lines.
        Some are indented
                more than others.
    Some should start at the first column.
    Some have "quoted text" in them.
    """;

Raw string literals can be combined with string interpolation to include braces in the output text. Multiple $ characters denote how many consecutive braces start and end the interpolation:

var location = $$"""
   You are at {{{Longitude}}, {{Latitude}}}
   """;

References
https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-11#raw-string-literals

required modifier in C# 11

- by mahmood 
public class Person
{
    public Person() { }

    [SetsRequiredMembers]
    public Person(string firstName, string lastName) =>
        (FirstName, LastName) = (firstName, lastName);

    public required string FirstName { get; init; }
    public required string LastName { get; init; }

    public int? Age { get; set; }
}

public class Student : Person
{
    public Student() : base()
    {
    }

    [SetsRequiredMembers]
    public Student(string firstName, string lastName) :
        base(firstName, lastName)
    {
    }

    public double GPA { get; set; }
}

The SetsRequiredMembers disables the compiler’s checks that all required members are initialized when an object is created. Use it with caution.

References
https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/required
https://youtu.be/9CDgPgWF9IY

Read characters from a string in C#

- by mahmood 
using System;
using System.IO;

public class CharsFromStr
{
    public static void Main()
    {
        string str = "Some number of characters";
        char[] b = new char[str.Length];

        using (StringReader sr = new StringReader(str))
        {
            // Read 13 characters from the string into the array.
            sr.Read(b, 0, 13);
            Console.WriteLine(b);

            // Read the rest of the string starting at the current string position.
            // Put in the array starting at the 6th array member.
            sr.Read(b, 5, str.Length - 13);
            Console.WriteLine(b);
        }
    }
}
// The example has the following output:
//
// Some number o
// Some f characters

References
https://learn.microsoft.com/en-us/dotnet/standard/io/how-to-read-characters-from-a-string

Deserialize XML to Object in C#

- by mahmood 
<?xml version="1.0" encoding="utf-8"?>
<Company xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Employee name="x" age="30" />
  <Employee name="y" age="32" />
 </Company>
using System.Xml.Serialization;

[XmlRoot(ElementName = "Company")]
public class Company

{
    public Company()
    {  
        Employees = new List<Employee>();
    }

    [XmlElement(ElementName = "Employee")]
    public List<Employee> Employees { get; set; }

    public Employee this[string name]
    {
        get { return Employees.FirstOrDefault(s => string.Equals(s.Name, name, 							StringComparison.OrdinalIgnoreCase)); }
    }
}

public class Employee
{
    [XmlAttribute("name")]
    public string Name { get; set; }

    [XmlAttribute("age")]
    public string Age { get; set; }
}
public static T DeserializeXml<T>(string str)
{
    var serializer = new XmlSerializer(typeof(T));
    object result;

    using (TextReader reader = new StringReader(str))
    {
        result = serializer.Deserialize(reader);
    }

    return (T) result;
}
var s = "--your xml string--";
var obj = Deserialize<CMS>(s);

References
https://www.delftstack.com/howto/csharp/deserialize-xml-to-object-in-csharp/
https://stackoverflow.com/questions/47158427/how-to-convert-xml-to-list-of-objects