使用了列舉來表示狀態，方便新增功能，提高程式碼可讀性：

程式碼如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
 
public class player1 : MonoBehaviour {
 
    /// <summary>
    /// 人物速度
    /// </summary>
    public float Speed = 5f;
 
    /// <summary>
    /// 移動狀態列舉
    /// </summary>
 

    public enum WalkIdle
    {
        Standalone,
        Up,
        Down,
        Left,
        Right,
        LeftUp,
        LeftDown,
        RightUp,
        RightDown
 
    }
 
    void FixedUpdate()
    {
 
        // 人物移動
        switch (GetWalkIdle())
        {
            case WalkIdle.Standalone:
 

 
                break;
            case WalkIdle.Up:
                transform.Translate(Vector3.up * Time.deltaTime * Speed);
                break;
            case WalkIdle.Down:
                transform.Translate(Vector3.down * Time.deltaTime * Speed);
                break;
            case
 
 WalkIdle.Left:
                transform.Translate(Vector3.left * Time.deltaTime * Speed);
                break;
            case WalkIdle.Right:
                transform.Translate(Vector3.right * Time.deltaTime * Speed);
                break;
            case WalkIdle.LeftUp:
                transform.Translate(Vector3.up * Time.deltaTime * Speed * 0.707f);
                transform.Translate(Vector3.left * Time.deltaTime * Speed * 0.707f);
                break;
            case WalkIdle.LeftDown:
                transform.Translate(Vector3.down * Time.deltaTime * Speed * 0.707f);
                transform.Translate(Vector3.left * Time.deltaTime * Speed * 0.707f);
                break;
            case WalkIdle.RightUp:
                transform.Translate(Vector3.up * Time.deltaTime * Speed * 0.707f);
                transform.Translate(Vector3.right * Time.deltaTime * Speed * 0.707f);
                break;
            case WalkIdle.RightDown:
                transform.Translate(Vector3.down * Time.deltaTime * Speed * 0.707f);
                transform.Translate(Vector3.right * Time.deltaTime * Speed * 0.707f);
                break;
        }
 
    }
 
    /// <summary>
    /// 獲得人物行走狀態
    /// </summary>
    /// <returns></returns>
    public WalkIdle GetWalkIdle()
    {
        if (Input.GetKey(KeyCode.W) && Input.GetKey(KeyCode.A))
        {
            return WalkIdle.LeftUp;
        }
        else if (Input.GetKey(KeyCode.W) && Input.GetKey(KeyCode.D))
        {
            return WalkIdle.RightUp;
        }
        else if (Input.GetKey(KeyCode.S) && Input.GetKey(KeyCode.A))
        {
            return WalkIdle.LeftDown;
        }
        else if (Input.GetKey(KeyCode.S) && Input.GetKey(KeyCode.D))
        {
            return WalkIdle.RightDown;
        }
        else if (Input.GetKey(KeyCode.W))
        {
            return WalkIdle.Up;
        }
        else if (Input.GetKey(KeyCode.A))
        {
            return WalkIdle.Left;
        }
        else if (Input.GetKey(KeyCode.S))
        {
            return WalkIdle.Down;
        }
        else if (Input.GetKey(KeyCode.D))
        {
            return WalkIdle.Right;
        }
        return WalkIdle.Standalone;
    }
 
}