/// <summary>设置扩展属性</summary>
/// <typeparam name="TDependEntity"></typeparam>
/// <param name="key"></param>
/// <param name="value"></param>
protected virtual void SetExtend <TDependEntity>(String key, Object value) where TDependEntity : Entity <TDependEntity>, new()
{
// 针对每个类型，仅注册一个事件
Type type = typeof(TDependEntity);
List <String> list = null;
if (!Depends.TryGetValue(type, out list))
{
list = new List <String>();
Depends.Add(type, list);
}
lock (Extends)
{
Extends[key] = value;
if (!list.Contains(key))
{
list.Add(key);
}
// 停止扩展属性的情况下不生效
if (!StopExtend && list.Count == 1)
{
Entity <TDependEntity> .Meta.OnDataChange += RemoveExtend;
}
}
}
/// <summary>获取扩展属性，获取数据时向指定的依赖实体类注册数据更改事件</summary>
/// <typeparam name="TDependEntity">依赖实体类，该实体类数据更改时清空所有依赖于实体类的扩展属性</typeparam>
/// <typeparam name="TResult">返回类型</typeparam>
/// <param name="key">键值</param>
/// <param name="func">回调</param>
/// <param name="cacheDefault">是否缓存默认值，可选参数，默认缓存</param>
/// <returns></returns>
protected virtual TResult GetExtend <TDependEntity, TResult>(String key, Func <String, Object> func, Boolean cacheDefault)
where TDependEntity : Entity <TDependEntity>, new()
{
Object value = null;
if (Extends.TryGetValue(key, out value))
{
return((TResult)value);
}
if (StopExtend)
{
return(default(TResult));
}
// 针对每个类型，仅注册一个事件
Type type = typeof(TDependEntity);
List <String> list = null;
if (!Depends.TryGetValue(type, out list))
{
list = new List <String>();
Depends.Add(type, list);
}
// 这里使用了成员方法GetExtend<TDependEntity>而不是匿名函数，为了避免生成包装类，且每次调用前实例化包装类带来较大开销
return((TResult)Extends.GetItem <Func <String, Object>, List <String> >(key, func, list, new Func <String, Func <String, Object>, List <String>, Object>(GetExtend <TDependEntity>), cacheDefault));
}
/// <summary>清理依赖于某类型的缓存</summary>
/// <param name="dependType">依赖类型</param>
void RemoveExtend(Type dependType)
{
// 停止扩展属性的情况下不生效
if (StopExtend)
{
return;
}
if (Depends == null || Extends.Count < 1)
{
return;
}
// 找到依赖类型的扩展属性键值集合
//List<String> list = Depends[dependType];
List <String> list = null;
if (!Depends.TryGetValue(dependType, out list) || list == null || list.Count < 1)
{
return;
}
lock (Extends)
{
// 清理该类型的所有扩展属性
foreach (String key in list)
{
//if (Extends.ContainsKey(key))
{
//if (Database.Debug)
//{
// Object value = Extends[key];
// Database.WriteLog("RemoveExtend({0}, {1}, {2})", key, this, value != null ? value.ToString() : "null");
//}
Extends.Remove(key);
}
}
list.Clear();
}
}