C# 带有委托的观察者可观察对象的超级简单示例

C# 带有委托的观察者/可观察对象的超级简单示例

csharp
public class ObservableObject
{
    public delegate void ValueChangedEventHandler(string value);
    public event ValueChangedEventHandler ValueChanged;
    public void OnValueChanged(string value)
    {
        ValueChanged?.Invoke(value);
    }
}

csharp
public class Observer
{
    public void HandleValueChanged(string value)
    {
        Console.WriteLine("Value changed: " + value);
    }
}

csharp
static void Main(string[] args)
{
    ObservableObject observableObject = new ObservableObject();
    Observer observer1 = new Observer();
    Observer observer2 = new Observer();
    observableObject.ValueChanged += observer1.HandleValueChanged;
    observableObject.ValueChanged += observer2.HandleValueChanged;
    observableObject.OnValueChanged("New value");
}

Value changed: New value
Value changed: New value