1. ue这里面，蓝图和cpp是两套运行顺序逻辑。首先是构造函数，cpp的构造函数是优于一切的，而蓝图的伪构造，其实是创建实例。BluePrintClass就是类似Unity里面的Prefab，拖到场景中才会创建实例。
2. 组件子Actor的构建，可以在构造函数中CreateDefaultSubobject <ChildActorComponent>进行；但是这个组件只是一个胶水，在蓝图里静态存在时，并不是真正的创建Actor（见下面大钊文章）。运行时子Actor的构建，可以GetWorld.SpawnActor进行。编辑器中如果想动态构建，最好全走蓝图，有一些蓝图节点蓝图能调用cpp中没有；也可以尝试写一些BluePrintLibrary。

《InsideUE4》GamePlay架构（一）Actor和Component - 知乎 (zhihu.com)

UE4中dynamic create component及ChildActorComponent未解析符号 问题_繁弱的博客-CSDN博客
UE4 中在 Actor 中动态 Create Component 与ChildActor 的 小笔记 (bbsmax.com)
《InsideUE4》GamePlay架构（一）Actor和Component - 知乎 (zhihu.com)

Unreal Engine C++ spawn actor and attach actor to component (AttachToComponent) GUNS IN CHARACTER. - YouTube

动态创建物体；
CreateDefaultSubobject只能在构造函数中使用
c++ - Unreal Engine 4. Different ways to instantiate the object - Stack Overflow

废代码记录

UChildActorComponent* ChildActorComponent = CreateDefaultSubobject<UChildActorComponent>("Slot");
    ChildActorComponent->SetChildActorClass(ASlot::StaticClass());
    // ChildActorComponent->SetupAttachment(RootComponent);
    ChildActorComponent->AttachToComponent(RootComponent, FAttachmentTransformRules::KeepRelativeTransform);

    auto subObj = CreateDefaultSubobject<ASlot>("Slot");//CreateDefaultSubobject是只能在cpp的构造函数中使用吗？
    auto subRoot = subObj->GetRootComponent();
    subRoot->AttachToComponent(RootComponent, FAttachmentTransformRules::KeepRelativeTransform);

    subObj->AttachToActor(this,  FAttachmentTransformRules::KeepRelativeTransform);
    childSlots.Emplace(subObj);

    //UE_LOG(TDLog, Error, TEXT("行列：%d, %d"), numberOfRows, numberOfRows);
    
    for (int i = 0; i < numberOfRows - 1; ++i)
    {
        for (int j = 0; j < numberOfColumns - 1; ++j)
        {
            // UChildActorComponent* ChildActorComponent =
            //  Cast< UChildActorComponent >
            // (
            //  FDatasmithActorImporter::ImportSceneComponent(
            //      UChildActorComponent::StaticClass(),
            //      AreaLightElement, ImportContext, Outer, UniqueNameProvider ) );
            //
            // ChildActorComponent->SetChildActorClass( TSubclassOf< AActor >
            //  ( LightShapeBlueprint->GeneratedClass ) );
    
            // UChildActorComponent* ChildActorComponent = CreateDefaultSubobject<UChildActorComponent>("Slot");
            // ChildActorComponent->SetChildActorClass(TSubclassOf<ASlot>());
            // ChildActorComponent->SetupAttachment(RootComponent);
    
            // const auto temp_childActorComponent = NewObject<UChildActorComponent>(this, UChildActorComponent::StaticClass());
            // UObject* outer = nullptr;
            // auto temp_imageCom = NewObject<ASlot>(outer);
            // temp_imageCom.registercom
            // temp_childActorComponent->SetChildActorClass(TSubclassOf<ASlot>());
            // temp_imageCom->AttachToComponent(this, FAttachmentTransformRules::KeepRelativeTransform);//SnapToTargetNotIncludingScale
    
            auto subObj = CreateDefaultSubobject<ASlot>("Slot");
            subObj->AttachToActor(this,  FAttachmentTransformRules::KeepRelativeTransform);
            childSlots.Emplace(subObj);
        }
    }