Tabs

Overview

Tabs derives from native System.Windows.Controls.TabControl (NaviusTabs) and TabItem (NaviusTabItem), collapsing the web contract’s four parts (Root/List/Tab/Panel) into these two types since TabItem.Header/Content already live together. Because native TabControl navigation doesn’t know about activation mode, loop, or RTL mirroring, NaviusTabs switches off KeyboardNavigation.DirectionalNavigation and reimplements arrow/Home/End/Enter/Space itself.

Usage

xmlns:tabs="clr-namespace:Navius.Wpf.Primitives.Controls.Tabs;assembly=Navius.Wpf.Primitives"

<tabs:NaviusTabs ActivationMode="automatic" Loop="True">
    <tabs:NaviusTabItem Value="account" Header="Account">
        <TextBlock Text="Account settings." />
    </tabs:NaviusTabItem>
    <tabs:NaviusTabItem Value="billing" Header="Billing">
        <TextBlock Text="Billing settings." />
    </tabs:NaviusTabItem>
</tabs:NaviusTabs>

Properties

Property	Type	Default	From	Description
Value	string?	null	NaviusTabs	Controlled/uncontrolled selected tab value; also driven by native selection (click). One Value DP covers both controlled and uncontrolled use, since TabControl already selects its first item on load.
ActivationMode	string	"automatic"	NaviusTabs	"automatic": focusing a tab via keyboard also selects it. "manual": arrows move focus only; Enter/Space/click selects.
Loop	bool	true	NaviusTabs	Arrow navigation wraps at edges when true; clamps at first/last when false.
Dir	string?	null	NaviusTabs	"ltr"/"rtl"; falls back to FlowDirection when unset.
Orientation	string	"horizontal"	NaviusTabs	"horizontal" or "vertical"; drives arrow-key axis (no native TabControl equivalent).
ActivationDirection	string	"none"	NaviusTabs	Read-only. One of "none"/"left"/"right"/"up"/"down", recomputed on every selection change from the old/new selected index and Orientation.
Value	string	""	NaviusTabItem	Identifies this tab; NaviusTabs uses it to derive/sync its own Value.
Header / Content	object	-	TabItem	Trigger content and panel content respectively, unified on one NaviusTabItem object.

Events

Event	Signature	Fires when
ValueChanged	RoutedEventHandler	The selected tab value changes (click or keyboard activation).

Keyboard interactions

Key	Behavior
ArrowRight (horizontal, ltr) / ArrowLeft (horizontal, rtl)	Moves to the next enabled tab.
ArrowLeft (horizontal, ltr) / ArrowRight (horizontal, rtl)	Moves to the previous enabled tab.
ArrowDown (vertical)	Moves to the next enabled tab.
ArrowUp (vertical)	Moves to the previous enabled tab.
Home / End	Moves to the first/last enabled tab.
Enter / Space	Selects the focused tab (required in manual mode; a harmless re-select in automatic mode).

In "automatic" mode, moving focus with an arrow key also selects the target and moves keyboard focus to it. In "manual" mode, arrows move roving focus only; selection requires Enter, Space, or a click. Loop=true (default) wraps at edges; Loop=false clamps (no movement past the first/last enabled tab). Disabled tabs are skipped entirely.

UIA mechanism

NaviusTabs/NaviusTabItem ship no custom AutomationPeer; they inherit TabControl’s TabControlAutomationPeer/TabItemAutomationPeer, which report native SelectionPattern and role="tab"/role="tabpanel" semantics for free. ActivationMode, Loop, RTL mirroring, and ActivationDirection are hand-rolled state with no UIA pattern equivalent, since WPF’s built-in navigation and automation model doesn’t represent them. The unit suite (TabsTests.cs) exercises automatic vs. manual activation, Loop wrap vs. clamp, RTL arrow mirroring, Home/End, disabled-tab skipping, and ActivationDirection recomputation; the M6 audit added ManualMode_SpaceOnFocusedTab_Selects to confirm Space activates a focused tab exactly like Enter (both share one activation branch in HandlePreviewKeyDown).

Web deltas

• Four web parts collapse to two WPF types: NaviusTabs (which also owns the List’s arrow-key navigation, since WPF’s internal TabPanel isn’t a separately addressable public part) and NaviusTabItem (unifying Tab trigger and Panel content, since TabItem.Header/Content already live on one object).
• KeepMounted on the Panel is dropped: native TabControl only ever instantiates one shared ContentPresenter bound to the selected item’s content, so there is no per-item persistent panel to keep hidden-but-mounted without a much larger custom-template rewrite. Documented Tier A tradeoff, not an oversight.
• DefaultValue collapses into Value: like NaviusRadioGroup, one Value DP is used both controlled and uncontrolled.
• data-navius-tabs/data-orientation/dir marker attributes are dropped; the equivalent state is queryable via native/added DPs (IsSelected, IsEnabled, Orientation, ActivationDirection) consumed directly by Style triggers.
• Disabled tabs map straight to TabItem.IsEnabled; there is no separate Disabled DP.
• M6 residual (not fixed): vertical-orientation arrow focus movement is exercised only indirectly by the unit suite, which asserts ActivationDirection rather than actual Up/Down focus traversal. Low risk since the same internal Move() method drives both axes, but a dedicated vertical focus-traversal test does not yet exist.

Captures

The Tabs Gallery page rendered at the pinned commit, in each theme.