如何在 Orchard 内容处理程序中动态添加内容部分？

Question

我有一个调用

的 Orchard 内容处理程序

Filters.Add(new Orchard.ContentManagement.Handlers.ActivatingFilter<MyPart>("User"));

在其构造函数中将MyPart 焊接到用户内容项。

如何根据内容项 ID 焊接 MyPart？

这里的问题是在调用构造函数时内容项尚未创建。我尝试通过覆盖 Activating() 来连接到生命周期，但这也不起作用，因为内容项还没有创建。

Answer 1

好吧，这个任务真的很难。这是我的解决方案。

1) 创建一个将内容部分焊接到内容项的扩展方法（遗憾的是，我们不能使用 ContentItemBuild.Weld()，因为没有机会传递内容项）

// adopted from ContentItemBuilder.Weld<>()
public static TPart Weld<TPart>(this Orchard.ContentManagement.ContentItem aContentItem)
  where TPart: Orchard.ContentManagement.ContentPart, new()
{
  var partName = typeof(TPart).Name;

  // obtain the type definition for the part
  var typePartDefinition = aContentItem.TypeDefinition.Parts.FirstOrDefault(p => p.PartDefinition.Name == partName);
  if (typePartDefinition == null) {
      // If the content item's type definition does not define the part; use an empty type definition.
      typePartDefinition = new Orchard.ContentManagement.MetaData.Models.ContentTypePartDefinition(
          new Orchard.ContentManagement.MetaData.Models.ContentPartDefinition(partName),
          new Orchard.ContentManagement.MetaData.Models.SettingsDictionary());
  }

  // build and weld the part
  var part = new TPart { TypePartDefinition = typePartDefinition };
  aContentItem.Weld(part); 

  return part;
}

2) 定义一个 StorageFilter 用于将内容部分动态焊接到内容项

public class BaseWeldBeforeStorageFilter<TPart, TRecord> : Orchard.ContentManagement.Handlers.IContentStorageFilter 
  where TPart: Orchard.ContentManagement.ContentPart, new()
  where TRecord: Orchard.ContentManagement.Records.ContentPartRecord
{
  // public
    public BaseWeldBeforeStorageFilter(Orchard.Data.IRepository<TRecord> aPartRecords)
    {
      mPartRecords = aPartRecords;
    }

    ...

    public void Loading(Orchard.ContentManagement.Handlers.LoadContentContext aContext)
    {
      // dynamically weld TPart to content item when condition is met (is a user, does record exist)
      if (aContext.ContentItem.Is<Orchard.Users.Models.UserPart>())
      {
        if (!aContext.ContentItem.Is<TPart>())
        {
          if (mPartRecords.Count(r => r.Id == aContext.ContentItem.Id) > 0)
            aContext.ContentItem.Weld<TPart>();
        }
      }
    }

    ...

  // private
    Orchard.Data.IRepository<TRecord> mPartRecords;
}

3) 为动态内容部分定义内容处理程序

public abstract class BasePartHandler<TPart, TRecord> : Orchard.ContentManagement.Handlers.ContentHandler
  where TPart: Orchard.ContentManagement.ContentPart<TRecord>, new()
  where TRecord: Orchard.ContentManagement.Records.ContentPartRecord, new()
{
  // public
    // the constructor of a content handler is called when a content item (e.g. user) is created
    public BasePartHandler(Orchard.Data.IRepository<TRecord> aPartRecords)
    {
      ...

      // add storage filter for dynamically welding TPart to content item
      Filters.Add(new BaseWeldBeforeStorageFilter<TPart, TRecord>(aPartRecords)); 

      // enable storing TPart to associated table
      Filters.Add(Orchard.ContentManagement.Handlers.StorageFilter.For<TRecord>(aPartRecords));

      ...

      // listen to user creation, update, removal...
      OnCreated<Orchard.Users.Models.UserPart>(UserCreated);
      ...
    }

    ...

  // private
    private void UserCreated(Orchard.ContentManagement.Handlers.CreateContentContext aContext, Orchard.Users.Models.UserPart aUserPart)
    {
      if (...) // condition for checking whether user 
        CreatePartRecordWhenNeededAndWeldPart(aContext.ContentItem, ...);
    }

    private void CreatePartRecordWhenNeededAndWeldPart(Orchard.ContentManagement.ContentItem aContentItem)
    {
      TPart lPart = aContentItem.Weld<TPart>();

      // assign record, adopted from StorageFilter.cs
      // todo: find a way to do it the "Orchard way" as this feels like hack
      lPart._record.Loader(r => 
        new TRecord {
          Id = aContentItem.Id, 
          ContentItemRecord = new Orchard.ContentManagement.Records.ContentItemRecord {Id = aContentItem.Id}
        });

      // there are situations where part record already exists in DB but part is not welded at this point, thus check for existing record to avoid
      //  - creating record multiple times 
      //  - NHibernate exception
      if (!mPartRecords.Table.Contains(lPart.Record))
        mPartRecords.Create(lPart.Record);
    }

    private Orchard.Data.IRepository<TRecord> mPartRecords;
}

目前，动态内容部分处理工作正常，但我仍然不确定如何在 Orchard 中正确创建内容部分记录（请参阅步骤 3 源代码中的待办事项提示）。