c# - 将字典值修改为 out 参数和引用

Question

我想创建一个实体-组件-系统示例。我有类似的组件

internal struct Position : IComponent
{
    public int X { get; set; }
    public int Y { get; set; }
}

和

internal struct Movementspeed : IComponent
{
    public float Value { get; set; }
}

哪个实现

internal interface IComponent
{
}

当遍历组件时，我想尽快找到它们。我想过创建一个字典，将组件类型作为键，将组件作为值。

internal class ComponentCollection
{
    public ComponentCollection()
    {
        components = new Dictionary<Type, object>();
    }

    private Dictionary<Type, object> components;

    public void AddComponent<T>(T component) // add a new component
    {
        Type componentType = typeof(T);
        components.Add(componentType, component as IComponent);
    }

    public void RemoveComponent(Type componentType) // remove the component by type
    {
        components.Remove(componentType);
    }

    public bool TryGetComponent<T>(out T component) // get the specified component
    {
        try
        {
            Type componentType = typeof(T);
            component = (T)components[componentType];
            return true;
        }
        catch (Exception)
        {
            component = default(T);
            return false;
        }
    }
}

出现了两个问题。

1. 如果有人使用 float movementspeed 创建了一个新的 MovementspeedComponent 并尝试添加它会怎样？有两个 float 会引发重复键异常。我只能添加实现 IComponent 接口(interface)的自定义结构组件以防止重复。

2. 当我尝试修改组件时，它们未被引用修改

   private static void Main(string[] args)
   {
       ComponentCollection components = new ComponentCollection();
       components.AddComponent(new Position());
       components.AddComponent(new Movementspeed());
   
       if (components.TryGetComponent(out Position fooPosition))
       {
           fooPosition.X++;
           Console.WriteLine(fooPosition.X); // prints 1
       }
   
       if (components.TryGetComponent(out Position barPosition))
       {
           Console.WriteLine(barPosition.X); // prints 0
       }
   
       Console.ReadLine();
   }
   

有什么建议吗？

Answer 1

What if someone creates a new MovementspeedComponent using float movementspeed

当我们每种类型都有一个对象/集合时，类型对键很有用，否则 Dictionary<Type, object>不太合适，键应该是唯一的。

When I try to modify the components they are not modified by reference

因为所有组件都是 struct是这行代码:

components.TryGetComponent(out Position fooPosition)

获取字典中结构的副本。引自 C# guide :

Structs are copied on assignment. When a struct is assigned to a new variable, all the data is copied, and any modification to the new copy does not change the data for the original copy. This is important to remember when working with collections of value types such as Dictionary.

What if someone creates a new MovementspeedComponent using float movementspeed and tries to add it?