C# Readonly Usage Explained

In C#, the readonly keyword is used to define read-only fields or read-only properties. It can be used in fields of classes, fields of structures, and auto-implemented properties of classes. Here is how the readonly keyword is used:

1. cannot be changed

public class MyClass {
    public readonly int MyField = 10;
}

// 使用只读字段
MyClass obj = new MyClass();
Console.WriteLine(obj.MyField);  // 输出：10

1. unchangeable

public class MyClass {
    public int MyProperty { get; } = 10;
}

// 使用只读属性
MyClass obj = new MyClass();
Console.WriteLine(obj.MyProperty);  // 输出：10

The values of read-only fields and properties are initialized at the time of declaration or in the constructor, so their values cannot be dynamically modified at runtime.

In general, the readonly keyword is used to define read-only fields or properties to ensure that their values remain constant throughout the object’s lifecycle. This can provide more reliable data protection and code security.