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Src/LiteDb/LiteDbDictionary.cs

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+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using LiteDB;
+
+namespace Net.BITKit.Database
+{
+    public class LiteDbDictionary<TKey, TValue> : IDictionary<TKey, TValue>, IDisposable where TKey : notnull
+    {
+        // 内部的 LiteDB 数据库实例
+        private readonly LiteDatabase _db;
+
+        // LiteDB 集合名称可以自定义，默认为 "kv"
+        private readonly ILiteCollection<KeyValueItem> _collection;
+
+        // 内部使用的键值项（POCO类）
+        private class KeyValueItem
+        {
+            // LiteDB 将此字段作为文档的 _id（主键）
+            [BsonId] public TKey Key { get; set; }
+            public TValue Value { get; set; }
+        }
+
+        public LiteDbDictionary()
+        {
+            _db = new LiteDatabase(":memory:");
+            _collection = _db.GetCollection<KeyValueItem>(typeof(TValue).Name);
+            _collection.EnsureIndex(x => x.Key);
+        }
+        
+        /// <summary>
+        /// 构造函数
+        /// connectionString 可以是磁盘文件（如 "Filename=MyData.db;Mode=Shared"）
+        /// 或内存数据库（如 ":memory:"）
+        /// </summary>
+        /// <param name="connectionString">数据库连接字符串</param>
+        /// <param name="collectionName">集合名称，默认 "kv"</param>
+        public LiteDbDictionary(string connectionString, string collectionName = "kv")
+        {
+            _db = new LiteDatabase(connectionString);
+            _collection = _db.GetCollection<KeyValueItem>(collectionName);
+            // 确保对键生成索引
+            _collection.EnsureIndex(x => x.Key);
+        }
+
+        #region IDictionary 实现
+
+        public TValue this[TKey key]
+        {
+            get
+            {
+                var bsonId = _db.Mapper.Serialize(typeof(TKey), key);
+                var item = _collection.FindById(bsonId);
+                if (item == null) throw new KeyNotFoundException($"Key '{key}' not found.");
+                return item.Value;
+            }
+            set
+            {
+                var item = new KeyValueItem { Key = key, Value = value };
+                _collection.Upsert(item);
+            }
+        }
+
+        public ICollection<TKey> Keys => _collection.FindAll().Select(x => x.Key).ToList();
+        public ICollection<TValue> Values => _collection.FindAll().Select(x => x.Value).ToList();
+        public int Count => _collection.Count();
+        public bool IsReadOnly => false;
+
+        public void Add(TKey key, TValue value)
+        {
+            if (ContainsKey(key))
+                throw new ArgumentException($"An element with the key '{key}' already exists.");
+            _collection.Insert(new KeyValueItem { Key = key, Value = value });
+        }
+
+        public bool ContainsKey(TKey key)
+        {
+            return _collection.Exists(x => x.Key.Equals(key));
+        }
+
+        public bool Remove(TKey key)
+        {
+            var bsonKey = _db.Mapper.Serialize(typeof(TKey), key);
+            return _collection.Delete(bsonKey);
+        }
+
+
+        public bool TryGetValue(TKey key, out TValue value)
+        {
+            var bsonKey = _db.Mapper.Serialize(typeof(TKey), key);
+            var doc = _collection.FindById(bsonKey);
+            if (doc == null)
+            {
+                value = default;
+                return false;
+            }
+
+            value = doc.Value;
+            return true;
+        }
+
+
+        public void Add(KeyValuePair<TKey, TValue> item)
+        {
+            Add(item.Key, item.Value);
+        }
+
+        public void Clear()
+        {
+            _collection.DeleteAll();
+        }
+
+        public bool Contains(KeyValuePair<TKey, TValue> item)
+        {
+            if (TryGetValue(item.Key, out var val))
+                return EqualityComparer<TValue>.Default.Equals(val, item.Value);
+            return false;
+        }
+
+        public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
+        {
+            foreach (var kv in this)
+            {
+                array[arrayIndex++] = kv;
+            }
+        }
+
+        public bool Remove(KeyValuePair<TKey, TValue> item)
+        {
+            if (Contains(item))
+                return Remove(item.Key);
+            return false;
+        }
+
+        public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
+        {
+            foreach (var item in _collection.FindAll())
+            {
+                yield return new KeyValuePair<TKey, TValue>(item.Key, item.Value);
+            }
+        }
+
+        IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+        #endregion
+
+        #region IDisposable 实现
+
+        public void Dispose()
+        {
+            _db?.Dispose();
+        }
+
+        #endregion
+    }
+}