private static IEntityPropertyMetadata FindBaseProperty(ref IEntityPropertyMetadataCollection properties, string name, ref ICollection <IEntityMetadata> ancestors)
{
if (properties == null)
{
return(null);
}
var baseEntity = properties.Entity.GetBaseEntity();
if (baseEntity != null)
{
ancestors = new List <IEntityMetadata>();
ancestors.Add(baseEntity);
}
while (baseEntity != null)
{
if (baseEntity.Properties.TryGet(name, out var property))
{
return(property);
}
baseEntity = baseEntity.GetBaseEntity();
if (baseEntity != null)
{
ancestors.Add(baseEntity);
}
}
return(null);
}
/// <summary>
/// <para>查找属性集合中指定成员路径对应的属性。</para>
/// <para>注：查找范围包括父实体的属性集。</para>
/// </summary>
/// <param name="properties">指定要查找的属性集合。</param>
/// <param name="path">指定要查找的成员路径，支持多级导航属性路径。</param>
/// <param name="match">属性匹配成功后的回调函数。</param>
/// <returns>返回找到的属性，如果没有指定指定成员路径的属性则返回空(null)。</returns>
public static EntityPropertyFindResult <T> Find <T>(this IEntityPropertyMetadataCollection properties, string path, T token, Func <EntityPropertyFindContext <T>, T> match = null)
{
if (string.IsNullOrEmpty(path))
{
return(EntityPropertyFindResult <T> .Failure(token));
}
Queue <IEntityMetadata> ancestors = null;
IEntityPropertyMetadata property = null;
var parts = path.Split('.');
for (int i = 0; i < parts.Length; i++)
{
if (properties == null)
{
return(EntityPropertyFindResult <T> .Failure(token));
}
//如果当前属性集合中不包含指定的属性，则尝试从父实体中查找
if (!properties.TryGet(parts[i], out property))
{
//尝试从父实体中查找指定的属性
property = FindBaseProperty(ref properties, parts[i], ref ancestors);
//如果父实体中也不含指定的属性则返回失败
if (property == null)
{
return(EntityPropertyFindResult <T> .Failure(token));
}
}
//如果回调函数不为空，则调用匹配回调函数
//注意：将回调函数返回的结果作为下一次的用户数据保存起来
if (match != null)
{
token = match(new EntityPropertyFindContext <T>(string.Join(".", parts, 0, i), token, property, ancestors));
}
//清空继承实体链
if (ancestors != null)
{
ancestors.Clear();
}
if (property.IsSimplex)
{
break;
}
else
{
properties = GetAssociatedProperties((IEntityComplexPropertyMetadata)property, ref ancestors);
}
}
//返回查找到的结果
return(new EntityPropertyFindResult <T>(token, property));
}
public MetadataEntity(IMetadata provider, string name, string baseName = null)
{
if (string.IsNullOrEmpty(name))
{
throw new ArgumentNullException(nameof(name));
}
_name = name.Trim();
_baseName = baseName;
_provider = provider ?? throw new ArgumentNullException(nameof(provider));
_properties = new MetadataEntityPropertyCollection(this);
}
