c# - 创建未知类型的实例

Question

我很确定有几种不同的方法可以做到这一点，因为我已经非常接近它但没有成功，但我想看看你对我的具体案例的看法.

有没有办法避免这种切换？

Resource r = null; < --Resource is the base class of block,rock,plant types.

switch (type) //type is a byte you get from somewhere on runtime
{
        //Then you instantiate that class type depending on that "type byte",
        //simply by comparing it to an enum lets say

    case ResourceType.Block:
        r = new Block();
        break;
    case ResourceType.Rock:
        r = new Rock();
        break;
    case ResourceType.Plant:
        r = new Plant();
        break;
 }

//Then you apply some data to that newly created 'resource"
r.id = id;

//Then you save that 'resource' into a dictionary of resources.
ResourceDatabase.Add(r.id, r);

Answer 1

我的方法是使用字典来构建映射。字典可以在运行时修改，并且可以在需要时使用反射动态填充。

var factory = new Dictionary<ResourceType, Func<Resource>>()
{
    { ResourceType.Block, () => new Block() },
    { ResourceType.Rock, () => new Rock() },
    { ResourceType.Plant, () => new Plant() },
};

Resource r = factory[type].Invoke();