Unity 无法序列化标准词典。这意味着它们不会在检查器中显示或编辑，
也不会在启动时实例化。一个经典的解决方法是将键和值存储在单独的数组中，并在启动时构造字典。

我们使用gitthub大佬的源码即可，此项目提供了一个通用字典类及其自定义属性抽屉来解决此问题。
源码地址：https://github.com/azixMcAze/Unity-SerializableDictionary

你可以选择下载源码，也可以直接复制我下面的代码，我把主要代码提出来了
SerializableDictionary.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.Serialization;
using UnityEngine;

public abstract class SerializableDictionaryBase
{
	public abstract class Storage {}

	protected class Dictionary<TKey, TValue> : System.Collections.Generic.Dictionary<TKey, TValue>
	{
		public Dictionary() {}
		public Dictionary(IDictionary<TKey, TValue> dict) : base(dict) {}
		public Dictionary(SerializationInfo info, StreamingContext context) : base(info, context) {}
	}
}

[Serializable]
public abstract class SerializableDictionaryBase<TKey, TValue, TValueStorage> : SerializableDictionaryBase, IDictionary<TKey, TValue>, IDictionary, ISerializationCallbackReceiver, IDeserializationCallback, ISerializable
{
	Dictionary<TKey, TValue> m_dict;
	[SerializeField]
	TKey[] m_keys;
	[SerializeField]
	TValueStorage[] m_values;

	public SerializableDictionaryBase()
	{
		m_dict = new Dictionary<TKey, TValue>();
	}

	public SerializableDictionaryBase(IDictionary<TKey, TValue> dict)
	{	
		m_dict = new Dictionary<TKey, TValue>(dict);
	}

	protected abstract void SetValue(TValueStorage[] storage, int i, TValue value);
	protected abstract TValue GetValue(TValueStorage[] storage, int i);

	public void CopyFrom(IDictionary<TKey, TValue> dict)
	{
		m_dict.Clear();
		foreach (var kvp in dict)
		{
			m_dict[kvp.Key] = kvp.Value;
		}
	}

	public void OnAfterDeserialize()
	{
		if(m_keys != null && m_values != null && m_keys.Length == m_values.Length)
		{
			m_dict.Clear();
			int n = m_keys.Length;
			for(int i = 0; i < n; ++i)
			{
				m_dict[m_keys[i]] = GetValue(m_values, i);
			}

			m_keys = null;
			m_values = null;
		}
	}

	public void OnBeforeSerialize()
	{
		int n = m_dict.Count;
		m_keys = new TKey[n];
		m_values = new TValueStorage[n];

		int i = 0;
		foreach(var kvp in m_dict)
		{
			m_keys[i] = kvp.Key;
			SetValue(m_values, i, kvp.Value);
			++i;
		}
	}

	#region IDictionary<TKey, TValue>
	
	public ICollection<TKey> Keys {	get { return ((IDictionary<TKey, TValue>)m_dict).Keys; } }
	public ICollection<TValue> Values { get { return ((IDictionary<TKey, TValue>)m_dict).Values; } }
	public int Count { get { return ((IDictionary<TKey, TValue>)m_dict).Count; } }
	public bool IsReadOnly { get { return ((IDictionary<TKey, TValue>)m_dict).IsReadOnly; } }

	public TValue this[TKey key]
	{
		get { return ((IDictionary<TKey, TValue>)m_dict)[key]; }
		set { ((IDictionary<TKey, TValue>)m_dict)[key] = value; }
	}

	public void Add(TKey key, TValue value)
	{
		((IDictionary<TKey, TValue>)m_dict).Add(key, value);
	}

	public bool ContainsKey(TKey key)
	{
		return ((IDictionary<TKey, TValue>)m_dict).ContainsKey(key);
	}

	public bool Remove(TKey key)
	{
		return ((IDictionary<TKey, TValue>)m_dict).Remove(key);
	}

	public bool TryGetValue(TKey key, out TValue value)
	{
		return ((IDictionary<TKey, TValue>)m_dict).TryGetValue(key, out value);
	}

	public void Add(KeyValuePair<TKey, TValue> item)
	{
		((IDictionary<TKey, TValue>)m_dict).Add(item);
	}

	public void Clear()
	{
		((IDictionary<TKey, TValue>)m_dict).Clear();
	}

	public bool Contains(KeyValuePair<TKey, TValue> item)
	{
		return ((IDictionary<TKey, TValue>)m_dict).Contains(item);
	}

	public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
	{
		((IDictionary<TKey, TValue>)m_dict).CopyTo(array, arrayIndex);
	}

	public bool Remove(KeyValuePair<TKey, TValue> item)
	{
		return ((IDictionary<TKey, TValue>)m_dict).Remove(item);
	}

	public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
	{
		return ((IDictionary<TKey, TValue>)m_dict).GetEnumerator();
	}

	IEnumerator IEnumerable.GetEnumerator()
	{
		return ((IDictionary<TKey, TValue>)m_dict).GetEnumerator();
	}

	#endregion

	#region IDictionary

	public bool IsFixedSize { get { return ((IDictionary)m_dict).IsFixedSize; } }
	ICollection IDictionary.Keys { get { return ((IDictionary)m_dict).Keys; } }
	ICollection IDictionary.Values { get { return ((IDictionary)m_dict).Values; } }
	public bool IsSynchronized { get { return ((IDictionary)m_dict).IsSynchronized; } }
	public object SyncRoot { get { return ((IDictionary)m_dict).SyncRoot; } }

	public object this[object key]
	{
		get { return ((IDictionary)m_dict)[key]; }
		set { ((IDictionary)m_dict)[key] = value; }
	}

	public void Add(object key, object value)
	{
		((IDictionary)m_dict).Add(key, value);
	}

	public bool Contains(object key)
	{
		return ((IDictionary)m_dict).Contains(key);
	}

	IDictionaryEnumerator IDictionary.GetEnumerator()
	{
		return ((IDictionary)m_dict).GetEnumerator();
	}

	public void Remove(object key)
	{
		((IDictionary)m_dict).Remove(key);
	}

	public void CopyTo(Array array, int index)
	{
		((IDictionary)m_dict).CopyTo(array, index);
	}

	#endregion

	#region IDeserializationCallback

	public void OnDeserialization(object sender)
	{
		((IDeserializationCallback)m_dict).OnDeserialization(sender);
	}

	#endregion

	#region ISerializable

	protected SerializableDictionaryBase(SerializationInfo info, StreamingContext context) 
	{
		m_dict = new Dictionary<TKey, TValue>(info, context);
	}

	public void GetObjectData(SerializationInfo info, StreamingContext context)
	{
		((ISerializable)m_dict).GetObjectData(info, context);
	}

	#endregion
}

public static class SerializableDictionary
{
	public class Storage<T> : SerializableDictionaryBase.Storage
	{
		public T data;
	}
}

[Serializable]
public class SerializableDictionary<TKey, TValue> : SerializableDictionaryBase<TKey, TValue, TValue>
{
	public SerializableDictionary() {}
	public SerializableDictionary(IDictionary<TKey, TValue> dict) : base(dict) {}
	protected SerializableDictionary(SerializationInfo info, StreamingContext context) : base(info, context) {}

	protected override TValue GetValue(TValue[] storage, int i)
	{
		return storage[i];
	}

	protected override void SetValue(TValue[] storage, int i, TValue value)
	{
		storage[i] = value;
	}
}

[Serializable]
public class SerializableDictionary<TKey, TValue, TValueStorage> : SerializableDictionaryBase<TKey, TValue, TValueStorage> where TValueStorage : SerializableDictionary.Storage<TValue>, new()
{
	public SerializableDictionary() {}
	public SerializableDictionary(IDictionary<TKey, TValue> dict) : base(dict) {}
	protected SerializableDictionary(SerializationInfo info, StreamingContext context) : base(info, context) {}

	protected override TValue GetValue(TValueStorage[] storage, int i)
	{
		return storage[i].data;
	}

	protected override void SetValue(TValueStorage[] storage, int i, TValue value)
	{
		storage[i] = new TValueStorage();
		storage[i].data = value;
	}
}

普通字典简单的使用

public class SerializedTest : MonoBehaviour {
    //普通字典
    public Dictionary<string, string> dictionary;

    private void Start() {
        //实例化字典
        dictionary = new Dictionary<string, string>();
        //添加键值对
        dictionary.Add("name1", "小明");
        dictionary["name2"] = "小红";
        //检查是否包含指定的键
        string key = "name1";
        Debug.Log($"是否包含键为{key}：{dictionary.ContainsKey(key)}");
        //检查是否包含指定的值
        string value = "小红";
        Debug.Log($"是否包含值为{value}：{dictionary.ContainsValue(value)}");
        //获取指定键的值
        Debug.Log($"获取键为name2的值：{dictionary["name2"]}");
        //移除键值对
        dictionary.Remove("name1");
        //获取键值对数量
        Debug.Log($"获取键值对数量：{dictionary.Count}");
        //清空字典
        dictionary.Clear();
    }
}

结果

可序列化字典简单的使用

和普通字典的使用方法一样，只需要把Dictionary换成SerializableDictionary，并且使用时不需要先实例化了

public class SerializedTest : MonoBehaviour {
    //可序列化字典
    public SerializableDictionary<string, string> serializableDictionary;

    private void Start() {
        //添加键值对
        serializableDictionary.Add("name1", "小明");
        serializableDictionary["name2"] = "小红";
        //检查是否包含指定的键
        string key = "name1";
        Debug.Log($"是否包含键为{key}：{serializableDictionary.ContainsKey(key)}");
        //获取指定键的值
        Debug.Log($"获取键为name2的值：{serializableDictionary["name2"]}");
        //移除键值对
        serializableDictionary.Remove("name1");
        //获取键值对数量
        Debug.Log($"获取键值对数量：{serializableDictionary.Count}");
        //清空字典
        //serializableDictionary.Clear();
    }
}

结果

运行时，在挂载的脚本上也可以直接显示字典的值