将类型转换为另一种类型 C#

Question

I want to add a component to an object with a type parameter, but it says it cannot be used like this:

void AddScript<T>(GameObject self)
    {
        self.AddComponent<T>();
    }

I tried searching for a solution but only found ways to converting a object to another object. I also tried boxing conversion like it said:

void AddScript<T>(GameObject self)
    {
        self.AddComponent<[Component]T>();
    }

But the compiler said that it was a type, and it was not valid.

So how do you convert a type to another type?

Answer 1

Since it's telling you that you have to pass a UnityEngine.Component type, you will most likely have to constrain your T to that type:

void AddScript<T>(GameObject self) where T : UnityEngine.Component
{
    self.AddComponent<T>();
}

Answer 2

You have to add the same Type constraint probably.

void AddScript<T>(GameObject self)
  where T : UnityEngine.Component {
 // ...
}

The where above is a type constraint which means that T must be any type that inherits from or is a Component .

Answer 3

The problem is that the type argument T you have created is less constrained than the type argument of self.AddComponent<T>() .

This is how AddComponent<T> is implemented for Unity objects:

public T AddComponent<T>() where T : Component
{
  return this.AddComponent(typeof (T)) as T;
}

So you will also need a type constraint that is either Component, or a derivative of Component.

Answer 4

The AddComponent method has a generic type constrant where T must be Component.

You can change your method singature as follows

void AddScript<T>(GameObject self) where T : Component
{
    self.AddComponent<T>();
}