xaml-ui

XAML is client presentation. Keep authority and protected validation out of code-behind.

Structure

• Keep static layout and styling in XAML. Build controls in code only for genuinely dynamic content or reusable custom controls.
• Keep named controls limited to elements code-behind actually accesses. Prefer existing containers, styles, and UI patterns over manual positioning or rebuilding static layout in code.
• Keep code-behind responsible for view state, presentation-only transformations, and translating input into a typed event or request. Do not make the window a second owner of authoritative or replicated state. Put reusable game behavior in its owning system, not the window.
• Let a BUI/EUI adapter own open/close lifecycle, message transport, and applying incoming state. The window should not call server services or decide whether an action is authorized.
• Treat client validation as user feedback. The server validates security-sensitive and authoritative requests.
• Find a nearby control using the same UI framework. Verify generated names, control types, constructors, and lifecycle APIs before relying on them.

Lifecycle and localization

• Subscribe once. Unsubscribe when the window closes or disposes if the event source can outlive the window; prevent duplicate subscriptions after reopen.
• If an asynchronous result or deferred callback can arrive after close/rebind, cancel it when supported or verify that the window still owns the result before changing controls.
• Refresh localized labels when culture changes if the window can remain open. Do not cache resolved text beyond the culture in which it was created.
• Localize visible labels, tooltips, placeholders, feedback, and generated rows. Use en-US by default; update ru-RU only when explicitly requested.
• Check long translated strings and culture refresh when Russian is in scope; otherwise verify the English UI states affected by the change.

Verify owner paths and edit-marker requirements before changing inherited files. Do not add markers to owner-local module paths. For code-behind boundaries see .agents/rules/architecture-and-ownership.md; for BUI contracts and message flow see .agents/skills/bound-user-interface/SKILL.md.

Choose the smallest build or UI behavior check that covers the changed surface and follow root AGENTS.md and .agents/skills/testing/references/testing-matrix.md. Documentation-only changes need diff checks; do not run a full build or every integration test by default.