Property Pattern in C#: What It Is and How to Use It

The property pattern in C# lets you check if an object has specific property values directly inside a switch or if statement. It simplifies code by matching properties of an object without writing extra variable checks.

How It Works

The property pattern in C# allows you to look inside an object and check its properties in a clean and readable way. Imagine you have a box and you want to know if it contains a red ball. Instead of opening the box and checking each item manually, the property pattern lets you ask directly, "Does this box have a ball that is red?"

In code, this means you can write conditions that match an object's properties without extra steps. The pattern looks like { PropertyName: value }, and you can use it inside switch or if statements to make decisions based on those properties.

Example

This example shows how to use the property pattern to check a person's age and city in a simple way.

csharp

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
    public string City { get; set; }
}

public class Program
{
    public static void Main()
    {
        var person = new Person { Name = "Alice", Age = 30, City = "New York" };

        if (person is { Age: >= 18, City: "New York" })
        {
            System.Console.WriteLine("Adult living in New York");
        }
        else
        {
            System.Console.WriteLine("Does not match criteria");
        }
    }
}

Output

Adult living in New York

When to Use

Use the property pattern when you want to check one or more properties of an object quickly and clearly. It is helpful when you have complex objects and want to avoid writing many separate if statements for each property.

For example, in user input validation, filtering data, or handling different cases in a switch statement based on object details, the property pattern makes your code easier to read and maintain.

Key Points

• The property pattern matches object properties directly in conditions.
• It improves code readability by reducing nested checks.
• Works well with switch expressions and if statements.
• Supports relational patterns like >= and <= inside property checks.

Key Takeaways

Property pattern lets you match object properties directly in conditions.

It simplifies code by avoiding multiple separate property checks.

Use it to write clear and concise if or switch statements.

Supports complex conditions like ranges inside property checks.

Ideal for filtering or branching logic based on object details.