What are some advanced usage patterns for dictionaries in C#?

What are some advanced usage patterns for dictionaries in C#?

In C#, dictionaries can be used in various advanced ways, such as using custom objects as keys, or implementing multi-value dictionaries. Would you like to explore a specific pattern?

Yes, can you explain how to use custom objects as keys?

Certainly! To use custom objects as keys, you need to override the GetHashCode and Equals methods in your class. This ensures that the dictionary can correctly identify unique keys. Would you like a code example?

Yes, please provide a code example.

Here's a simple example:

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

    public override int GetHashCode() {
        return Name.GetHashCode() ^ Age.GetHashCode();
    }

    public override bool Equals(object obj) {
        if (obj is Person other) {
            return Name == other.Name && Age == other.Age;
        }
        return false;
    }
}

var dictionary = new Dictionary<Person, string>();
var person1 = new Person { Name = "Alice", Age = 30 };
var person2 = new Person { Name = "Bob", Age = 25 };

dictionary[person1] = "Engineer";
dictionary[person2] = "Designer";

That's really helpful! What about multi-value dictionaries?