using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public static class Extension 
{




    public static void MoveControlByTranslate(this Transform obj, float m_speed)
    {
        if (Input.GetKey(KeyCode.W) | Input.GetKey(KeyCode.UpArrow)) //前
        {
        obj.transform.Translate(Vector3.forward * m_speed * Time.deltaTime);
        }
        if (Input.GetKey(KeyCode.S) | Input.GetKey(KeyCode.DownArrow)) //后
        {
         obj.transform.Translate(Vector3.forward * -m_speed * Time.deltaTime);
        }
        if (Input.GetKey(KeyCode.A) | Input.GetKey(KeyCode.LeftArrow)) //左
        {
          obj.transform.Translate(Vector3.right * -m_speed * Time.deltaTime);
        }
        if (Input.GetKey(KeyCode.D) | Input.GetKey(KeyCode.RightArrow)) //右
        {
           obj.transform.Translate(Vector3.right * m_speed * Time.deltaTime);
        }
    }
}

扩展方法可以使代码更简洁，注意格式必须是静态类，静态方法，用this来指明扩展的类。

别挂在object上了，难怪一直提示我错误