Custom controls in a custom upm package not showing up in ui builder

I verified that moving the custom control class to the unity project script folder causes it to appear in the ui builder. I also checked the "show package files" toggle and other configs that show editor controls etc but to no avail. Is there a way to move custom controls to a package and have them show up in the ui builder right now?

 

I saw the Unity Sample UI Builder/toolkit have a custom control window following the UI Document window in the UI builder, but my own project do not have this window. I create a subclass of visualelement, but no custom sontrol shows up. what should i do to fix this problem?

edit: tossrock is right.

 

I also have this issue. Creating a custom class which extends VisualElement does not yield an entry in the CustomControls section of the Library subwindow of the UI Builder.

edit: Figured this out - for anyone coming across this post in the future, in order to appear within the UIBuilder, a custom control must:

1. Inherit from VisualElement, eg

class NewControl : VisualElement

2. Have a public UxmlFactory inner class which inherits from UxmlFactory templatized with the custom control name.

So, a minimal namespaced custom control which will appear in the UIBuilder is as follows:

Code (CSharp):

1.  
2. using UnityEngine.UIElements;
3.  
4. namespace com.mygame.ui
5. {
6.     class NewControl: VisualElement
7.     {
8.         new public class UxmlFactory : UxmlFactory<NewControl>
9.         {
10.  
11.         }
12.     }
13. }
14.  
15.  

 

I am also running into this in 2021.3.8f1. It works when it's part of the root project, but moving it to a Package causes it to not be found and generates the exception: "Element '<element_name>' has no registered factory method."

 

Make sure you've added the package to your Assembly Definitions file in Unity https://docs.unity3d.com/Manual/ScriptCompilationAssemblyDefinitionFiles.html.