我试图将ScriptManager分配给ObjectManager，并使用了以下行：

ObjectManager = GameObject.Find("ScriptManager");

我已经检查了多次，以确保“ScriptManager”拼写正确，我甚至尝试直接从Unity复制粘贴名称。
我在运行时收到此错误：
“UnassignedReferenceException：尚未分配采矿的变量ObjectManager。您可能需要在检查器中分配采矿脚本的ObjectManager变量。UnityEngine.GameObject.GetComponent[T]（）（at<3be1a7ff939c43f181c0a10b5a0189ac>：0）Mining.Sell（）（at Assets/Mining.cs：49）”
遗憾的是，我不能直接从检查器中分配变量，因为带有代码的对象是使用Prefab加载的。
下面是完整的代码：

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

public class Mining : MonoBehaviour
{

public GameObject ObjectManager;
public Text WorkerCountText;
public float MiningSpeed;

public float WorkersInMine;
public float MiningMultiplyer;

public Collider2D collider;
public GameObject DropDown;

private float WorkerCount;

private float MineWorth;
private float Cash;

// Start is called before the first frame update
void Start()
{
    ObjectManager = GameObject.Find("ScriptManager");
    collider = GetComponent<Collider2D>();
    DropDown.SetActive(false);
}

// Update is called once per frame
void Update()
{
    Cash = ObjectManager.GetComponent<GenerateItems>().Money;
    WorkerCount = ObjectManager.GetComponent<GenerateItems>().Workers;
    MineWorth = ObjectManager.GetComponent<GenerateItems>().MineCost;
    
    WorkerCountText.text = "Workers:" + WorkerCount;  
   
}

public void Sell()
{
    ObjectManager.GetComponent<GenerateItems>().Money = Cash + MineWorth;
    Object.Destroy (this);
}
}