How to register event handler to controls of UXML? (UIElements)

Hi, I have a question about how to register event handler to controls of UXML.

Especially, OnClick() for Button and OnValueChanged for almost field controls. I know that there is SerializedObject binding mechanism, but I want to hook for custom logic from C# script.

Wihtout UXML, I can create button by new Button(myHandler); but I dont know that how to access controls in UXML from script and register my handler to each controls.

Thanks.