How to assign component to Uproperty from within class defaults

In C++ I have this property for a component.

UPROPERTY(EditAnywhere, BlueprintReadOnly, meta = (AllowPrivateAccess = "true"), Category = "Attachment")
USceneComponent* SomeComponent;

In the engine, when I edit the property, I have a dropdown of component classes. When I select one it looks like it tries to create a new instance.

I’d instead like to drag one of the actor’s components in and set it that way. Or if the dropdown list had a list of components in the actor.

Is this possible? Unity has similar behavior which is kindof an essential Unity pattern.

In Unreal I can only think to do this in code like in a construction script which isn’t as user friendly.


I am not really sure what you mean but it sounds like you are looking for TSubclassOf.
Here is a Link:

It’s more like how it is in Unity here starting at 3:08.

You can assign existing object references to variables. I have an existing Component I want to assign to a variable. TSubclassOf is a way to tell the component what class to spawn at run time.


Sorry, I misunderstood.

My Engine is currently building so I cannot check this in my CPP but I think what you are after is the UPROPERTY(Instanced)
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In Blueprint, you can access the value using by checking the box “Instance Editable”.

Done building and tried it out using
“UPROPERTY(Instanced, EditInstanceOnly)”
and it seemed to work out :slight_smile:

Ooooh, OK. I think I tried Instanced but without EditInstanceOnly.

This is one of the more confusing parts. I’ve been wishing there was a youtube video explaining this in detail since reading about the property specifiers it isn’t clear enough. It still confuses me sometimes and I’ve been using Unreal 4 since 1.0

Good to know that it helped!

Yeah, I agree that it is a bit confusing.

Maybe you can use this page instead as I believe that it is more descriptive and generally have more information: