DateRangePicker

Overview

DateRangePicker composes the same trigger + NaviusAnchoredPopup + NaviusCalendar anatomy as NaviusDatePicker (its NaviusDatePickerBase parent), adding a two-pick commit model on top: the first day picked sets Start, the second sets End (ordered via DateRangeCommitEngine) and closes the popup; Escape reverts both endpoints to their state when the popup opened. The calendar runs in CalendarSelectionMode.SingleRange purely so Start/End/middle days render as selected; commits never go through the native mode’s Shift-to-extend semantics.

Usage

xmlns:dateRangePicker="clr-namespace:Navius.Wpf.Primitives.Controls.DateRangePicker;assembly=Navius.Wpf.Primitives"

<dateRangePicker:NaviusDateRangePicker Value="{Binding StayDates, Mode=TwoWay}"
                                       Placeholder="Select dates" />

Properties

Property	Type	Default	From	Description
`Value`	`NaviusDateRange`	`NaviusDateRange.Empty`	`NaviusDateRangePicker`	Two-way bindable by default. Either endpoint may be `null` mid-pick.
`IsOpen`	`bool`	`false`	`NaviusDatePickerBase`	Two-way bindable; also settable via Enter/Space/ArrowDown when closed.
`Placeholder`	`string?`	`null`	`NaviusDatePickerBase`	Muted trigger text shown while `Value.IsEmpty`.
`Side`	`PlacementSide`	`Bottom`	`NaviusDatePickerBase`	Popup placement side.
`Align`	`PlacementAlign`	`Start`	`NaviusDatePickerBase`	Popup placement alignment (matches the web contract’s `NaviusDateRangePickerContent` default `Align="start"`).
`SideOffset`	`double`	`6`	`NaviusDatePickerBase`
`AlignOffset`	`double`	`0`	`NaviusDatePickerBase`
`DisplayText`	`string?`	`null`	`NaviusDatePickerBase`	Read-only. The formatted trigger label (`"start - end"`, `"start - "` while the second pick is pending, or the placeholder).
`HasSelection`	`bool`	`false`	`NaviusDatePickerBase`	Read-only. Drives placeholder-muting trigger styling.

Events

Event	Signature	Fires when
`ValueChanged`	`RoutedEventHandler`	On every committed endpoint change: first pick, second pick, and an Escape revert that actually changed the value.

Keyboard interactions

Key	Behavior
`Enter` / `Space` / `ArrowDown` (trigger, popup closed)	Opens the popup (inherited from `NaviusDatePickerBase`).
`Escape` (popup open)	Reverts both endpoints to the value captured when the popup opened, then closes.
`Enter` / `Space` (a focused calendar day)	Commits that day as the next pick: first pick fills Start, second fills End and closes.
Arrow keys / `PageUp` / `PageDown` / `Home` / `End` (inside the calendar)	Native `System.Windows.Controls.Calendar` day-grid navigation; does not commit a pick.
Outside press	Dismisses the popup without reverting whatever was already committed.

Per the M6 audit, only the open-when-closed keys, Escape, and the pick-commit engine are actually unit-tested; native Calendar’s own in-grid navigation and outside-press dismissal are exercised as inherited platform behavior, not independently driven by a test.

UIA mechanism

NaviusDateRangePickerAutomationPeer (a FrameworkElementAutomationPeer) reports AutomationControlType.Custom with localized control type "date range picker" (the native DatePickerAutomationPeer shape), plus a read-only IValueProvider surfacing "start - end" (or "start - " mid-pick, or empty while unset, never the placeholder) and IExpandCollapseProvider over IsOpen. The web contract’s popup role="dialog" has no direct equivalent; ExpandCollapse plus focus moved into the calendar on open is the native WPF idiom instead. Verified by automation-peer round-trip assertions in DateRangePickerTests.cs, plus the M6-audit-added OnOpened_WithRealCalendarPart_SwitchesToSingleRangeAndSyncsSelectionWithoutThrowing, which applies a real template first (prior tests never called ApplyTemplate(), so CalendarPart stayed null and the SingleRange switch/selection repaint were never actually exercised against a real native Calendar).

Web deltas

The two endpoint segmented NaviusDateInputs, the hidden bubble inputs, the role="group" control wrapper, and the Granularity/MinValue/MaxValue passthroughs are not ported in this wave (the DateInput family is a concurrent, separately-owned port). The trigger instead shows a plain read-only "start - end" display formatted per CultureInfo.CurrentCulture; composing editable endpoint fields into the trigger is a follow-up.
ZitsCalendar (a styled-layer component with no source in Navius.Primitives at all) is replaced by NaviusCalendar, a Tier A control deriving System.Windows.Controls.Calendar and inheriting its native keyboard model and CalendarAutomationPeer for free, re-templated to tokens.
The web’s Popover Portal/Positioner/Popup composition is replaced by NaviusAnchoredPopup directly: Side/Align/SideOffset/AlignOffset are flat properties on the picker root rather than a separate Positioner part.
NaviusDateRange is a readonly record struct over DateTime? (not DateOnly, to match System.Windows.Controls.Calendar’s own value type); the web contract’s Ordered() helper is unnecessary because DateRangeCommitEngine always orders on commit, so a typed-backwards range can never occur here (unlike the web, where typing a start date after an end date via the segmented inputs is not auto-normalized, moot in this port since no endpoint inputs exist yet).
Known residual: no validation logic exists for cross-endpoint constraints, and no endpoint-level MinValue/MaxValue constraints are ported in this wave at all (see the passthroughs bullet above).
Doc-only correction (M6 audit): Themes/DateRangePicker.xaml (and Calendar.xaml/ DatePicker.xaml) previously claimed to NOT be merged into Generic.xaml, “same precedent as Select.xaml”; both halves of that claim were false (all three, plus Select.xaml, are merged into Generic.xaml). No functional impact, comment-accuracy only.