3. #mvpconf
Beneficiários do Evento:
APAE-Associação de Pais e Amigos dos
Excepcionais
Lar da Criança Ninho de Paz
Para quem quiser doar outros valores além das inscrições:
CAIXA ECONÔMICA FEDERAL
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ITAU UNIBANCO AS
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CNPJ 53.372.454/0001-50
4. #mvpconf
Giovanni Bassi
Categorias de premiação:
Visual Studio/C#
Primeiro ano premiado:
2009
Número de prêmios MVPs:
9
/GBassi
/giggio.tech
/giggiobassi
@giovannibassi
Biografia
Programador, Microsoft MVP, Não gerente
blog.lambda3.com.br, podcast.lambda3.com.br, dotnetarchitects.net, nodebr, dockersp
Escalador e ciclista
blog.lambda3.com.br
podcast.lambda3.com.br
8. Acreditamos que a diversidade, em
suas diversas expressões, deve ser
respeitada e valorizada, e que uma
sociedade mais diversa é uma
sociedade melhor.
diversidade.tech
14. Acreditamos que a diversidade, em
suas diversas expressões, deve ser
respeitada e valorizada, e que uma
sociedade mais diversa é uma
sociedade melhor.
diversidade.tech
30. public static int DiceSum(IEnumerable<object> values)
{
var sum = 0;
foreach (var item in values)
{
if (item is int val)
sum += val;
else if (item is IEnumerable<object> subList)
sum += DiceSum(subList);
}
return sum;
}
https://docs.microsoft.com/dotnet/csharp/pattern-matching
http://bit.ly/cspatternmatching
32. case 0:
break;
case int val:
sum += val;
break;
case PercentileDie die:
sum += die.Multiplier * die.Value;
break;
https://docs.microsoft.com/dotnet/csharp/pattern-matching
public static int DiceSum(IEnumerable<object> values)
{
var sum = 0;
foreach (var item in values)
{
switch (item)
{
}
}
return sum;
}
http://bit.ly/cspatternmatching
33. case 0:
break;
case int val:
sum += val;
break;
case PercentileDie die:
sum += die.Multiplier * die.Value;
break;
https://docs.microsoft.com/dotnet/csharp/pattern-matching
case IEnumerable<object> subList when subList.Any():
sum += DiceSum(subList);
break;
case IEnumerable<object> subList:
break;
case null:
break;
default:
throw new InvalidOperationException("unknown");
public static int DiceSum(IEnumerable<object> values)
{
var sum = 0;
foreach (var item in values)
{
switch (item)
{
}
}
return sum;
}
http://bit.ly/cspatternmatching
35. void M()
{
var (name, company) = Person.Get();
WriteLine($"{name}, {company}");
}
class Person
{
public string Name { get; set; }
public string Company { get; set; }
public void Deconstruct(out string name, out string company)
{
name = Name;
company = Company;
}
public static Person Get() => new Person { Name = "…", Company = "…" };
} https://docs.microsoft.com/dotnet/csharp/tupleshttp://bit.ly/cstuplas
36. var numbers = (one: 1, two: 2);
var (uno, due) = numbers;
WriteLine($"{uno}, {due}");
https://docs.microsoft.com/dotnet/csharp/tuples
http://bit.ly/cstuplas
37. if (int.TryParse("1", out int result))
WriteLine(result);
if (int.TryParse("1", out var result2))
WriteLine(result2);
https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#out-variables
http://bit.ly/csoutvars
38. (int x, int y) GetCoordinates() => (1, 2);
var (_, y) = GetCoordinates();
https://docs.microsoft.com/dotnet/csharp/discards
http://bit.ly/csdiscards
40. if (int.TryParse("1", out _))
WriteLine("It is a number!");
https://docs.microsoft.com/dotnet/csharp/discards
http://bit.ly/csdiscards
41. object o = 1;
if (o is Person p)
WriteLine(p.Company);
else if (o is null)
WriteLine("null");
else if (o is var _)
WriteLine("Unknown");
https://docs.microsoft.com/dotnet/csharp/discards
http://bit.ly/csdiscards
42. ref int Find(int[,] matrix, Func<int, bool> predicate)
{
for (int i = 0; i < matrix.GetLength(0); i++)
for (int j = 0; j < matrix.GetLength(1); j++)
if (predicate(matrix[i, j]))
return ref matrix[i, j];
throw new InvalidOperationException("Not found");
}
void M()
{
var matrix = new [,] { { 1, 2, 3, 4, 5 }, { 6, 7, 8, 42, 10 } };
ref var item = ref Find(matrix, val => val == 42);
WriteLine(item);
item = 24;
WriteLine(matrix[1, 3]);
}
https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#ref-locals-and-returns
http://bit.ly/csreflocals
43. public ExpressionBodiedMembers(string name) => Name = name;
~ExpressionBodiedMembers() => WriteLine("Finalized!");
private string name;
public string Name
{
get => name;
set => name = value;
}
https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#more-expression-bodied-members
http://bit.ly/csmaisebm
44. private string a = GetA() ?? throw new Exception();
private static string GetA() => throw new Exception();
https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#throw-expressions
http://bit.ly/csexpthrow
45. int sixteen = 0b0001_0000;
int thirtyTwo = 0b0010_0000;
int sixtyFour = 0b0100_0000;
int oneHundredTwentyEight = 0b1000_0000;
long oneHundredBillions = 100_000_000_000;
double AvogadroConstant = 6.022_140_857_747_474e23;
decimal GoldenRatio = 1.618_033_988_749M;
https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#numeric-literal-syntax-improvements
http://bit.ly/csnumlit
46. double Average(IEnumerable<int> ns)
{
double Divide(double a, double b)
{
if (b == 0) throw new DivideByZeroException();
return a / b;
}
var sum = ns.Sum();
return Divide(sum, ns.Count());
}
https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#local-functions
http://bit.ly/cslocalfunc
47. void Add1AndSumAll(int[] ms)
{
IEnumerable<int> Sum1(IEnumerable<int> ns)
{
foreach (var n in ns)
yield return n + 1;
}
if (ms == null) throw new NullReferenceException();
WriteLine(Sum1(ms).Sum());
}
https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#local-functions
http://bit.ly/cslocalfunc
49. public async ValueTask<int> SumAsync(IEnumerable<ValueTask<int>> ns)
{
var sum = 0;
foreach (var nTask in ns)
{
var n = await nTask;
sum += n;
}
return sum;
}
https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#generalized-async-return-types
http://bit.ly/csasyncgeneral
56. void M(int i, int j) { }
void N()
{
M(i: 2, 3);
}
https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/non-trailing-named-arguments.md
http://bit.ly/csntna
57. var m = 0b_101; //5
var n = 0x_00C0; // 192
https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/leading-separator.md
http://bit.ly/cs_num
58. class Base
{
private protected int f;
}
class DerivedInSameAssembly : Base
{
void M()
{
var x = base.f;
}
}
class DerivedInOtherAssembly : Base
{
void M()
{
var x = base.f; //error
}
}
https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/private-protected.md
http://bit.ly/csprpr
59. Vector Add(in Vector v1, in Vector v2)
{
v1 = default(Vector); // not OK!!
v1.X = 0; // not OK!!
Foo(ref v1.X); // not OK!!
// OK:
return new Vector(v1.X +v2.X, v1.Y + v2.Y);
}
https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types
http://bit.ly/csmodin
61. public static Ponto Subtrai(ref this Ponto p1, ref Ponto p2) =>
new Ponto(p1.X - p2.X, p1.Y - p2.Y);
void Ref()
{
Ponto p1 = new Ponto(1, 2), p2 = new Ponto(3, 4);
var pResultado = p1.Subtrai(ref p2);
p1.Subtrai(ref new Ponto()); // não compila
new Ponto().Subtrai(ref p1); // não compila
}
https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/readonly-ref.md#refin-extension-methods
http://bit.ly/csextref
63. ref readonly Vector FetchOrigin() => ref origin;
void M()
{
var v1 = new Vector(1, 2, 3);
var v2 = new Vector(4, 5, 6);
var vSum = Add(v1, v2);
ref readonly var origin = ref FetchOrigin();
}
private readonly Vector origin = new Vector(0, 0, 0);
https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types
http://bit.ly/csretrefro
64. ref readonly var origin = ref FetchOrigin();
var origin2 = FetchOrigin(); // copy created
https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types
http://bit.ly/csretrefro
65. readonly struct Ponto
{
public Ponto(float x, float y)
{
X = x;
Y = y;
}
public float X { get; }
public float Y { get; }
private readonly static Ponto origem = new Ponto();
public static ref readonly Ponto Origem => ref origem;
}
https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types#readonly-struct-type
http://bit.ly/csrostruct
66. ref readonly var p = ref Ponto.Origem;
var x = p.X; // sem cópia
https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types#readonly-struct-type
http://bit.ly/csrostruct
68. ref struct TwoSpans<T>
{
// pode ter campos desde que não sejam classes
public Span<T> first;
public Span<T> second;
}
// erro: arrays of ref-like types are not allowed.
TwoSpans<int>[] arr = null;
https://docs.microsoft.com/en-us/dotnet/csharp/reference-semantics-with-value-types#ref-struct-type
69. readonly ref struct ReadOnlyRefPoint2D
{
public int X { get; }
public int Y { get; }
public ReadOnlyRefPoint2D(int x, int y) =>
(X, Y) = (x, y);
}
https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types#readonly-ref-struct-type
71. public class Cartesian { public int X { get; } public int Y { get; } }
public class Polar
{
public static bool operator is(Cartesian c, out double R, out double Theta)
{
R = Math.Sqrt(c.X * c.X + c.Y * c.Y);
Theta = Math.Atan2(c.Y, c.X);
return c.X != 0 || c.Y != 0;
}
}
void M()
{
var c = new Cartesian(3, 4);
if (c is Polar(var R, _)) WriteLine(R);
}
https://github.com/dotnet/csharplang/blob/master/proposals/patterns.md
76. void N(string? aNullableString, bool condition) {
WriteLine(aNullableString.Length); // warning
if (aNullableString != null)
WriteLine(aNullableString); // no warning
if (!string.IsNullOrWhiteSpace(aNullableString))
WriteLine(aNullableString!.Length); // I know better
var anotherNullableString = condition ? "Hello" : aNullableString;
WriteLine(anotherNullableString.Length); // warning
var yetAnotherNullableString = condition ? "Hello" : null;
WriteLine(yetAnotherNullableString.Length); // warning
string nonNullableString = null; //warning
WriteLine(nonNullableString); // no warning
}
https://github.com/dotnet/csharplang/blob/master/proposals/nullable-reference-types.md
https://github.com/dotnet/roslyn/blob/features/NullableReferenceTypes/docs/features/NullableReferenceTypes/README.md
77. async Task M()
{
foreach await (var i in GetStream())
WriteLine(i);
}
IAsyncEnumerable<int> GetStream() => new[] { 1, 2, 3 }.ToAsyncEnumerable();
async IAsyncEnumerable<int> MyIterator()
{
for (int i = 0; i < 100; i++)
{
await Task.Delay(1000);
yield return i;
}
}
https://github.com/dotnet/csharplang/blob/master/proposals/async-streams.md
78. using await (IAsyncDisposable resource = await store.GetRecordAsync(…)) { … }
class Foo : IAsyncDisposable
{
public async Task DisposeAsync()
{
await ...
}
}
https://github.com/dotnet/csharplang/blob/master/proposals/async-streams.md
79. interface I
{
void M() { WriteLine("I.M"); }
}
class C : I { } // OK
void M()
{ I i = new C();
i.M(); // prints "I.M"
}
https://github.com/dotnet/csharplang/blob/master/proposals/default-interface-methods.md
80. 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);
…
}
class Person(string First, string Last);
https://github.com/dotnet/csharplang/blob/master/proposals/records.md
81. extension class Enrollee extends Person
{
// static field
static Dictionary<Person, Professor> enrollees = new Dictionary<Person, Professor>();
// instance method
public void Enroll(Professor supervisor) { enrollees[this] = supervisor; }
// instance property
public Professor Supervisor => enrollees.TryGetValue(this, out var supervisor) ? supervisor : null;
// static property
public static ICollection<Person> Students => enrollees.Keys;
// instance constructor
public Person(string name, Professor supervisor) : this(name) { this.Enroll(supervisor); }
}
https://github.com/dotnet/csharplang/issues/192