Позволяет проверять значения свойств/полей любого объекта
<br>
Базовый пример без дополнительного использования прочих паттернов:
Switch:
```csharp
Building building = GetBuilding();
switch (building)
{
case { Type: "Castle", Level: 3 }:
Console.WriteLine("Your castle is at maximum level!");
break;
}
```
If:
```csharp
Building building = GetBuilding();
if (building is { Type: "Castle", Level: 3 })
{
Console.WriteLine("Your castle is at maximum level!");
}
```
<br>
Использование вместе с Type Pattern и Var Pattern
```csharp
object obj = GetObject();
if (obj is Person { Name: var name })
{
Console.WriteLine(
quot;This is a Person. Name is: {name}");
}
```
<br>
Relational pattern и Logical pattern
```csharp
Person person = GetPerson();
if (person is { Name: "John" or "Jane", Health: > 50 })
{
Console.WriteLine("This is either John or Jane with more than 50 health points");
}
```
<br>
When pattern (без Var Pattern не обойтись)
```csharp
Person person = GetPerson();
if (person is { Name: "John" } and { Health: var health } when health > 50)
{
Console.WriteLine(quot;This is John with {health} health points");
}
```
<br>
Negated pattern
```csharp
Person person = GetPerson();
if (person is { Name: not "John" })
{
Console.WriteLine("This person is not John");
}
```
<br>
Использование вместе с as
```csharp
object obj = new Person("John", "Doe", 35);
var person = obj as Person { Age: var age } switch
{
Person { Age: >= 18 } => quot;Person is older than 18, actual age: {age}",
_ => "Person is under 18 or not a person"
};
```
<br>
<br>
Прочие примеры
```csharp
public static string GetWeatherDescription(Weather weather) => weather switch
{
{ Temperature: (< 0), Sky: Clear } => "Холодно и ясно",
{ Temperature: (> 30), Sky: Cloudy } => "Жарко и облачно",
{ Temperature: (> 30) and (< 45), Sky: Sunny } => "Тепло и солнечно",
{ Rainfall: (> 0) and (< 10), Sky: Rainy } => "Легкий дождь",
_ => "Неизвестная погода"
};
```