Skip to content

Property pattern

Context: The property pattern matches an object’s properties against nested patterns.

public class Point
{
    public int X { get; set; }
    public int Y { get; set; }
}

Point p = new Point { X = 10, Y = 20 };
if (p is { X: 10, Y: 20 })
{
    Console.WriteLine("Point (10,20)");
}

In switch expression

string quadrant = p switch
{
    { X: > 0, Y: > 0 } => "Q1",
    { X: < 0, Y: > 0 } => "Q2",
    { X: < 0, Y: < 0 } => "Q3",
    { X: > 0, Y: < 0 } => "Q4",
    _ => "On axis"
};

Real-world usage example

Validation rules: Use property pattern in a switch expression to validate complex objects without multiple if statements.

Example: In FluentValidation, you could implement custom rules using property pattern.