Dotnet 5

New stuff in .net 5

To compile a .net standard library for .net 5.0

Change TargetFramework

 <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
 </PropertyGroup>

To TargetFrameworks so it can compile for .net standard and .net 5.0

  <PropertyGroup>
    <TargetFrameworks>netstandard2.0;.net5.0</TargetFrameworks>
  </PropertyGroup>

# Simplified Console apps

To make it easier for people to learn c# 9 you can remove alot of the code on a console app.

You can replace

 namespace CsharpDemo
  {
       class Program
       {
            static void Main(string[] args)
            {     
                  Console.WriteLine(lastName);
            }  
       }      
  }

With

 System.Console.Write("Hello world!");

Records with C#

immutable classes

  namespace CsharpDemo
  {

        public record Person(string firstName, string lastName);

  }

Init properties

Properties that can only have values set when class is being created

public class Employee
{
    public string Name { get; init; }

    public string position { get; init; }
}

Deconstructors

pull properties into variables

        var person = new Person("Ken", "Tucker");
        var (firstName, lastName) = person;

Json Serialization

Can serialize records and classes with init properties

        var person = new Person("Ken", "Tucker");

        var employee = new Employee(){Name = "Ken", position = "Dev"};

        string json = System.Text.Json.JsonSerializer.Serialize(person);

        var person2 = System.Text.Json.JsonSerializer.Deserialize<Person>(json);

        string json2 = System.Text.Json.JsonSerializer.Serialize(employee);

        var employee2 = System.Text.Json.JsonSerializer.Deserialize<Employee>(json2);

Networking changes

Added ability to tell if network call was cancelled or was a timeout

       var cts = new CancellationTokenSource();
        try
        {
            // Pass in the token.
            using var response = await _client.GetAsync("https://localhost:5001/Time?seconds=14", cts.Token);
        }
        // If the token has been canceled, it is not a timeout.
        catch (TaskCanceledException ex) when (cts.IsCancellationRequested)
        {
            // Handle cancellation.
            Console.WriteLine("Canceled: " + ex.Message);
        }
        catch (TaskCanceledException ex)
        {
            // Handle timeout.
            Console.WriteLine("Timed out: " + ex.Message);
        }

Sample code available in this repo

https://github.com/vb2ae/SpaceCoastDotNet5Demo