DevExpress XAF:获取SubCollection集合

Question

我有3个类: GrandFother，人，孩子

public class GrandFother: BaseObject
{
[Association("GrandFother_Persons")]
//......
public XPCollection<Persons > GFChilds
{
   get
    {
        return GetCollection<Persons >("GFChilds");
    }
}
}

public class Persons: BaseObject
{
[Association("Persons_Childs")]
// Other code ...
public XPCollection<Child> Childs
{
   get
    {
        return GetCollection<Child>("Childs");
    }
}
//Other code ...
}

public class Child: BaseObject
{
[Association("Persons_Childs")]
// Code ...
}

现在，我想要的是，在GrandFother类中，我想要获得与属于祖父的人相关联的所有孩子的列表

例如：

GrangFother1 has two Persons: Person1, Person2.  
Person1 has 2 childs: Per1Ch1, Per1Ch2.    
Person2 has 2 childs: Per2Ch1, Per2Ch2

因此，在Class Grandfother中添加一个XPCollection<Child>，它将包含: Per1Ch1、Per1Ch2、Per2Ch1、Per2Ch2，如果可能的话，还可以使用排序选项。

谢谢。

Answer 1

您可以使用[NonPersistent]集合属性。

[NonPersistent]
public XPCollection<Child> GrandChildren
{
    get
    {
        var result = new XPCollection<Child>(Session, GFChilds.SelectMany(x => x.Childs));

        // sorting
        SortingCollection sortCollection = new SortingCollection();
        sortCollection.Add(new SortProperty("Name", SortingDirection.Ascending));
        xpCollectionPerson.Sorting = sortCollection;

        return result;
    }
}

但是您可能不需要XPCollection<Child> - IList<Child>通常就可以了。

[NonPersistent]
public IList<Child> GrandChildren
{
    get
    {
        return GFChilds
                  .SelectMany(x => x.Childs)
                  .OrderBy(x => x.Name);
    }
}