NetPonto - The Future Of C# - NetConf Edition
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The document discusses various new features in C# and .NET, including: - Async Main method allowing async entry points - Inferred tuple element names for cleaner tuple syntax - Default literal expressions avoiding unnecessary casts - Non-trailing named arguments for more flexible calling syntax - Pattern matching and switch expressions for more control flows - Reference semantics for value types for improved performance - And more proposals still in development like nullable reference types, ranges, and patterns. It also provides links to documentation and code repositories for further reading.
![static async Task Main(string[] args)
{
int[] numbers = { 0b1, 0b10, 0b100, 0b1000, 0b1_0000, 0b10_0000 };
int result = await SumOfSquaresAsync(numbers);
WriteLine(result);
}
static Task<int> SumOfSquaresAsync(int[] numbers)
=> Task.FromResult(numbers.Select(i => i * i).Sum());
static async Task<int> Main(string[] args)
https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-1#async-main
https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.1/async-main.md](https://image.slidesharecdn.com/netponto20180915-futurecsharp-180916174405/85/NetPonto-The-Future-Of-C-NetConf-Edition-4-320.jpg)
![[field: SomeThingAboutFieldAttribute]
public int SomeProperty { get; set; }
https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#attach-attributes-to-the-backing-fields-for-auto-implemented-properties
https://github.com/dotnet/csharplang/issues/42](https://image.slidesharecdn.com/netponto20180915-futurecsharp-180916174405/85/NetPonto-The-Future-Of-C-NetConf-Edition-17-320.jpg)
![int* pArr = stackalloc int[3] { 1, 2, 3 };
int* pArr2 = stackalloc int[] { 1, 2, 3 };
Span<int> arr = stackalloc[] { 1, 2, 3 };
https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#stackalloc-arrays-support-initializers
https://github.com/dotnet/csharplang/issues/1286](https://image.slidesharecdn.com/netponto20180915-futurecsharp-180916174405/85/NetPonto-The-Future-Of-C-NetConf-Edition-18-320.jpg)
![unsafe struct S
{
public fixed int myFixedField[10];
}
class C
{
static S s = new S();
unsafe public void M()
{
fixed (int* ptr = s.myFixedField)
{
int p = ptr[5];
}
}
}
unsafe struct S
{
public fixed int myFixedField[10];
}
class C
{
static S s = new S();
unsafe public void M()
{
int p = s.myFixedField[5];
}
}
https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#indexing-fixed-fields-does-not-require-pinning
https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.3/indexing-movable-fixed-fields.md](https://image.slidesharecdn.com/netponto20180915-futurecsharp-180916174405/85/NetPonto-The-Future-Of-C-NetConf-Edition-19-320.jpg)
![https://github.com/dotnet/roslyn/blob/features/range/docs/features/range.md
var slice = array[4..10];
switch (x)
{
case 0..10:
break;
}
foreach (var i in 0..10)
{
WriteLine(string.Join(",", (0..i).Select(j => i * j)));
}](https://image.slidesharecdn.com/netponto20180915-futurecsharp-180916174405/85/NetPonto-The-Future-Of-C-NetConf-Edition-23-320.jpg)
NetPonto - The Future Of C# - NetConf Edition
- 3. Paulo Morgado • PauloMorgado.NET • @PauloMorgado • github.com/paulomorgado • stackoverflow.com/users/402366/paulo-morgado • slideshare.net/PauloJorgeMorgado • www.facebook.com/paulomorgado.net • revista-programar.info/author/pmorgado/ • luisabreu.github.io/csharp7pt/ • www.fca.pt/pt/catalogo- pesquisa/?filtros=2&q=Paulo+Morgado
- 4. static async Task Main(string[] args) { int[] numbers = { 0b1, 0b10, 0b100, 0b1000, 0b1_0000, 0b10_0000 }; int result = await SumOfSquaresAsync(numbers); WriteLine(result); } static Task<int> SumOfSquaresAsync(int[] numbers) => Task.FromResult(numbers.Select(i => i * i).Sum()); static async Task<int> Main(string[] args) https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-1#async-main https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.1/async-main.md
- 5. https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-1#default-literal-expressions https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.1/target-typed-default.md int result = await SumOfSquaresAsync(numbers, default(CancellationToken));int result = await SumOfSquaresAsync(numbers, default);
- 6. int count = 5; string label = "Colors used in the map"; var pair = (count: count, label: label); int count = 5; string label = "Colors used in the map"; var pair = (count, label); // element names are "count" and "label" https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-1#inferred-tuple-element-names https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.1/infer-tuple-names.md
- 8. https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-2#non-trailing-named-arguments https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/non-trailing-named-arguments.md void M(int arg1, string arg2, bool arg3 = false); M(1, arg2: "s", true); // valid in C# 7.3 M(arg2: "s", 0); // not valid M(arg2: "s", 0, arg3: true); // not valid
- 9. https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-2#leading-underscores-in-numeric-literals https://github.com/dotnet/roslyn/pull/20449 var b = 0b_1111_0000; var h = 0x_FF_00;
- 10. ref T Choice<T>(bool condition, ref T consequence, ref T alternative) { if (condition) { return ref consequence; } else { return ref alternative; } } https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/conditional-ref.md ref T Choice<T>(bool condition, ref T consequence, ref T alternative) { return ref condition ? ref consequence : ref alternative; }
- 13. // initialization ref VeryLargeStruct refLocal = ref veryLargeStruct; // reassigned, refLocal refers to different storage. refLocal = ref anotherVeryLargeStruct; https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#ref-local-variables-may-be-reassigned
- 14. void M!<D>(D d) where D : Delegate { } void M2<E>(E e) where E : Enum { } unsafe void M3<T>(T *p) where T : unmanaged { } https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#enhanced-generic-constraints
- 15. var tuple = ("", 10); if (tuple == ("", 10)) // true if (("", 10) == (null, 5.2)) // false if (("", 1, true) == (false, 5)) /* Error CS8384 Tuple types used as operands of an == or != operator must have matching cardinalities. But this operator has tuple types of cardinality 3 on the left and 2 on the right. */ https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#tuples-support--and- https://github.com/dotnet/csharplang/issues/190
- 16. public class B { public B(int i, out int j) => j = i; } public class D : B { public D(int i) : base(i, out var j) { WriteLine($"The value of 'j' is {j}"); } } https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#extend-expression-variables-in-initializers https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.3/expression-variables-in-initializers.md
- 17. [field: SomeThingAboutFieldAttribute] public int SomeProperty { get; set; } https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#attach-attributes-to-the-backing-fields-for-auto-implemented-properties https://github.com/dotnet/csharplang/issues/42
- 18. int* pArr = stackalloc int[3] { 1, 2, 3 }; int* pArr2 = stackalloc int[] { 1, 2, 3 }; Span<int> arr = stackalloc[] { 1, 2, 3 }; https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#stackalloc-arrays-support-initializers https://github.com/dotnet/csharplang/issues/1286
- 19. unsafe struct S { public fixed int myFixedField[10]; } class C { static S s = new S(); unsafe public void M() { fixed (int* ptr = s.myFixedField) { int p = ptr[5]; } } } unsafe struct S { public fixed int myFixedField[10]; } class C { static S s = new S(); unsafe public void M() { int p = s.myFixedField[5]; } } https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#indexing-fixed-fields-does-not-require-pinning https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.3/indexing-movable-fixed-fields.md
- 22. https://github.com/dotnet/csharplang/blob/master/proposals/nullable-reference-types.md string? n = "world"; var x = b ? "Hello" : n; // string? var y = b ? "Hello" : null; // string? or error var z = b ? 7 : null; // Error today, could be int?
- 23. https://github.com/dotnet/roslyn/blob/features/range/docs/features/range.md var slice = array[4..10]; switch (x) { case 0..10: break; } foreach (var i in 0..10) { WriteLine(string.Join(",", (0..i).Select(j => i * j))); }
- 24. https://github.com/dotnet/csharplang/blob/master/proposals/patterns.md static string M(Person person) { return person switch { Professor (_, var ln, var s) => $"Dr. {ln}, Professor of {s}", Student (var fn, _, var (_, ln, _)) => $"{fn}, Student of Dr. {ln}", { LastName: "Campbell", FirstName: var fn } => $"Please, enroll, {fn}", _ => "Come back next year!" }; }
- 25. https://github.com/dotnet/csharplang/blob/master/proposals/async-streams.md#iasyncdisposable public interface IAsyncDisposable { Task DisposeAsync(); }
- 26. https://github.com/dotnet/csharplang/blob/master/proposals/async-streams.md#iasyncenumerable--iasyncenumerator public interface IAsyncEnumerable<out T> { IAsyncEnumerator<T> GetAsyncEnumerator(); } public interface IAsyncEnumerator<out T> { Task<bool> WaitForNextAsync(); T TryGetNext(out bool success); }
- 27. interface ILogger { void Log(LogLevel level, string message); } class ConsoleLogger : ILogger { // send message public void Log(LogLevel level, string message) { } } https://github.com/dotnet/csharplang/blob/master/proposals/default-interface-methods.md interface ILogger { void Log(LogLevel level, string message); void Log(Exception ex) => Log(LogLevel.Error, ex.ToString()); } class ConsoleLogger : ILogger { // send message public void Log(LogLevel level, string message) { } }
- 28. https://github.com/dotnet/csharplang/blob/master/proposals/default-interface-methods.md interface ILogger { void Log(LogLevel level, string message); void Log(Exception ex) => Log(LogLevel.Error, ex.ToString()); } class TelemetryLogger : ILogger { // send message public void Log(LogLevel level, string message) { } // capture crash dump and send message public void Log(Exception ex) { } }
- 29. class Person(string First, string Last); class Person : IEquatable<Person> { public string First { get; } public string Last { get; } public Person(string First, string Last) => (this.First, this.Last) = (First, Last); public void Deconstruct(out string First, out string Last) => (First, Last) = (this.First, this.Last); public bool Equals(Person other) => other != null && First == other.First && Last == other.Last; public override bool Equals(object obj) => obj is Person other ? Equals(other) : false; public override int GetHashCode() => GreatHashFunction(First, Last); … }
- 38. * Para quem não puder preencher durante a reunião, iremos enviar um email com o link à tarde
- 39. 15/09/2018 – Lisboa 24/11/2018 – Lisboa Reserva estes dias na agenda! :)