NHibernate AliasToBean转换器关联

本文关键字：关联 转换器 AliasToBean NHibernate | 更新日期: 2023-09-27 18:08:53

我试图使用下面的语句来获得一个实体与我之后的字段:

retVal = session.CreateCriteria(typeof(MyEntity))
            .CreateAlias("MyEntityProperty", "MyEntityProperty")
            .Add(Restrictions.Eq("MyEntityProperty.Year", year))
            .SetProjection(
                Projections.Distinct(
                    Projections.ProjectionList()
                        .Add(Projections.Property("Property1"), "Property1")
                        .Add(Projections.Property("Property2"), "Property2")
                        .Add(Projections.Property("MyEntityProperty.RegisteredUser"), "MyEntityProperty.RegisteredUser")
                        .Add(Projections.Property("MyEntityProperty.CompanyInfo"), "MyEntityProperty.CompanyInfo")
                                                )
            )
            .SetResultTransformer(Transformers.AliasToBean(typeof(MyEntity)))
            .List<MyEntity>()
            .Cast<BaseMyEntity>();

MyEntity是我想要返回的实体，MyEntityProperty是MyEntity的一个属性，MyEntity是另一个实体(MyEntityProperty类型)。

我得到的错误是Could not find a setter for property 'MyEntityProperty.RegisteredUser' in class 'MyEntity'

AliasToBean转换器不能处理子实体吗?还是我还需要做些什么才能让它起作用?

NHibernate AliasToBean转换器关联

这是我的杰作…我用它来变换任何投影深度。把它拿出来，像这样使用:

.SetResultTransformer(new DeepTransformer<MyEntity>())

它可以用于任何ValueType属性，many-to-one引用以及动态对象…

public class DeepTransformer<TEntity> : IResultTransformer
    where TEntity : class
{
    // rows iterator
    public object TransformTuple(object[] tuple, string[] aliases)
    {
        var list = new List<string>(aliases);
        var propertyAliases = new List<string>(list);
        var complexAliases = new List<string>();
        for(var i = 0; i < list.Count; i++)
        {
            var aliase = list[i];
            // Aliase with the '.' represents complex IPersistentEntity chain
            if (aliase.Contains('.'))
            {
                complexAliases.Add(aliase);
                propertyAliases[i] = null;
            }
        }
        // be smart use what is already available
        // the standard properties string, valueTypes
        var result = Transformers
             .AliasToBean<TEntity>()
             .TransformTuple(tuple, propertyAliases.ToArray());
        TransformPersistentChain(tuple, complexAliases, result, list);
        return result;
    }
    /// <summary>Iterates the Path Client.Address.City.Code </summary>
    protected virtual void TransformPersistentChain(object[] tuple
          , List<string> complexAliases, object result, List<string> list)
    {
        var entity = result as TEntity;
        foreach (var aliase in complexAliases)
        {
            // the value in a tuple by index of current Aliase
            var index = list.IndexOf(aliase);
            var value = tuple[index];
            if (value.IsNull())
            {
                continue;
            }
            // split the Path into separated parts
            var parts = aliase.Split('.');
            var name = parts[0];
            var propertyInfo = entity.GetType()
                  .GetProperty(name, BindingFlags.NonPublic 
                                   | BindingFlags.Instance 
                                   | BindingFlags.Public);
            object currentObject = entity;
            var current = 1;
            while (current < parts.Length)
            {
                name = parts[current];
                object instance = propertyInfo.GetValue(currentObject);
                if (instance.IsNull())
                {
                    instance = Activator.CreateInstance(propertyInfo.PropertyType);
                    propertyInfo.SetValue(currentObject, instance);
                }
                propertyInfo = propertyInfo.PropertyType.GetProperty(name, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public);
                currentObject = instance;
                current++;
            }
            // even dynamic objects could be injected this way
            var dictionary = currentObject as IDictionary;
            if (dictionary.Is())
            {
                dictionary[name] = value;
            }
            else
            {
                propertyInfo.SetValue(currentObject, value);
            }
        }
    }
    // convert to DISTINCT list with populated Fields
    public System.Collections.IList TransformList(System.Collections.IList collection)
    {
        var results = Transformers.AliasToBean<TEntity>().TransformList(collection);
        return results;
    }
}

我是不是把事情弄得太复杂了

不需要在子实体上设置字段，我所需要做的就是引用实体字段本身:

.Add(Projections.Property("MyEntityProperty"), "MyEntityProperty")

和nHibernate填充得很好。

但是我很高兴我问了，因为我得到了Radim的非常有用的代码:-)

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