了解列表为何固定抽象方法类型

Question

我用两个抽象方法创建了一个类。在一种方法中，根据抽象方法List中的返回类型的要求，在列表中返回通用类型U。在我的第二种方法中，我只是按抽象方法中返回类型的要求返回U，但出现类型错误错误CS0029：无法隐式转换类型LB.HexSphereBuild.HexTile' toHexTile'我不明白为什么这是隐式转换？特别是因为所有类型都在LB.HexSphereBuild命名空间下，除了我的使用LB.HexSphereBuild的公共抽象类AStarFindPath之外；请帮忙using System.Collections;using System.Collections.Generic;using UnityEngine;using LB.Managers;using LB.HexSphereBuild;namespace LB.AStarPathFinding{    public abstract class AStarFindPath<T,U> : MonoBehaviour{        public virtual void FindPath<T>(Vector3 startPos, Vector3 targetPos) {        }        // Method 1        public abstract U NodeFromWorldPoint<T,U> (Vector3 worldPos);        // Method 2        public abstract List<U> GetNodeNeighbours<U> (U node);    }}这是继承我的抽象类的类using System.Collections;using System.Collections.Generic;using UnityEngine;using LB.Managers;using LB.AStarPathFinding;namespace LB.HexSphereBuild{    [RequireComponent (typeof(PlanetBuildManager))]    public class AStarHexSphere: AStarFindPath<Hexsphere,HexTile>    {        private HexSphere _hexSphereObj;        void Awake ()        {            // Reference to HexSphere             _hexSphereObj = gameObject.GetComponent<PlanetBuildManager> ().hexSphereObj;        }        override public HexTile NodeFromWorldPoint<HexSphere,HexTile> (Vector3 worldPos )        {            int startNodeIndex = _hexSphereObj.GetHexIndexFromPoint (worldPos);            int startNodeIndex = _hexSphereObj.GetHexIndexFromPoint (worldPos);            HexTile startHex =  _hexSphereObj.Hexes[startNodeIndex];// error CS0029: Cannot implicitly convert type `LB.HexSphereBuild.HexTile' to `HexTile'            return startHex;        }        override public List<HexTile> GetNodeNeighbours<HexTile> (HexTile node )        {            List<HexTile> neighbours = new List<HexTile>();            List<int> hexNeighboursIndices = new List<int>();            int hexIndex =0;            _hexSphereObj.GetNeighbors (hexIndex, ref hexNeighboursIndices);            return neighbours;        }

Answer 1

您已经定义了T和U，再次在方法中定义它们意味着T所有方法中的可能是不同的类型。那不是您想要的，删除方法上的泛型：

public abstract class AStarFindPath<T,U> : MonoBehaviour

{

    public virtual void FindPath(Vector3 startPos, Vector3 targetPos) 

    {

    }

    // Method 1

    public abstract U NodeFromWorldPoint(Vector3 worldPos);

    // Method 2

    public abstract List<U> GetNodeNeighbours(U node);

}