Fix Picker selection when SelectedItem is removed from ItemsSource by jpd21122012 · Pull Request #34299 · dotnet/maui

jpd21122012 · 2026-03-02T19:01:20Z

Description of Change

Fixes incorrect selection behavior in Picker when the selected item is removed from ItemsSource.

Previously, if the selected item was removed, Picker preserved the previous SelectedIndex, which could result in selecting a different item that now occupies the same index.

This caused index-based selection instead of identity-based selection.

Root Cause

GetSelectedIndex() returned the previous SelectedIndex when SelectedItem was no longer found in the collection.

This caused the control to keep an index that now pointed to a different item.

Fix

If the SelectedItem is no longer present in the collection, the control now returns -1, clearing the selection.

Verified Scenarios

Removing selected item clears selection.
Removing item before selected preserves the selected object.
Reordering items preserves the selected object.

Fixes #33307

github-actions · 2026-03-02T19:01:30Z

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.sh | bash -s -- 34299

Or

Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.ps1) } 34299"

dotnet-policy-service · 2026-03-02T19:01:44Z

Hey there @@jpd21122012! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

jpd21122012 · 2026-03-17T17:14:40Z

Hi, just checking if this PR could be reviewed for the upcoming 10.6 servicing release.

This fix ensures that Picker selection is updated correctly when the current SelectedItem is removed from the ItemsSource, preventing stale or inconsistent selection state.

The change is minimal and scoped to selection state handling, without affecting public APIs, so it should be safe for servicing.

Let me know if any additional scenarios should be validated 👍

MauiBot · 2026-03-22T01:49:42Z

🤖 AI Summary

📊 Expand Full Review — db83806 · [Picker] Fix test expectation when removing selected item

🔍 Pre-Flight — Context & Validation

Issue: #33307 - The Picker is still binding to the property and reacts to data changes after the page is closed.
PR: #34299 - Fix Picker selection when SelectedItem is removed from ItemsSource
Platforms Affected: Windows, Android (identity-based selection fix is cross-platform logic)
Files Changed: 1 implementation (Picker.cs), 1 test (PickerTests.cs)

Key Findings

Root Cause: GetSelectedIndex() fell back to the previous SelectedIndex when SelectedItem was no longer found in the collection. This caused index-based rather than identity-based selection.
Fix Approach: A new GetSelectedIndexForCollectionMutation() method returns -1 (not stale index) when SelectedItem is not found. Used in RemoveItems(), AddItems(), and ResetItems() instead of the original GetSelectedIndex().
Test change: Updated TestItemsSourceCollectionChangedRemoveAtEndSelected to assert -1/null when selected item is removed (previously expected last remaining item — now considered incorrect behavior).
New tests added: 3 new unit tests covering: clear on removal, preserve on unrelated removal, preserve on insertion.
Inline review feedback: Copilot PR reviewer flagged duplicate code between GetSelectedIndex and GetSelectedIndexForCollectionMutation; PR author kept them separate intentionally for safety of the fix.
kubaflo concern: "I'm pretty sure this PR will regress some other aspects of the picker" — followed by running device tests and UI tests.
Test type: Unit tests (src/Controls/tests/Core.UnitTests/PickerTests.cs)
Gate result: ✅ PASSED (pre-confirmed)
Prior agent review: Yes — MauiBot summary present; labels: s/agent-reviewed, s/agent-approved, s/agent-fix-pr-picked

Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
PR	PR #34299	Add `GetSelectedIndexForCollectionMutation()` returning -1 when item not found; use in mutation handlers	✅ PASSED (Gate)	`Picker.cs`, `PickerTests.cs`	Original PR

🔧 Fix — Analysis & Comparison

Fix Candidates

#	Source	Approach	Test Result	Files Changed	Notes
1	claude-opus-4.6	Direct removed-item detection: `e.OldItems.Contains(SelectedItem)` in RemoveItems(); `ItemsSource.IndexOf(SelectedItem) < 0` in ResetItems()	✅ PASS (49/49)	`Picker.cs`	Inline, no new method
2	claude-sonnet-4.6	Item-identity verification in `ClampSelectedIndex()`: after clamping, verify `ItemsSource[newIndex] == SelectedItem`, force -1 if stale	✅ PASS (49/49)	`Picker.cs`	Single change point, no new method
3	gpt-5.3-codex	Notification-level invalidation: clear stale selection in `CollectionChanged` handler before dispatching to AddItems/RemoveItems/ResetItems	✅ PASS (50/50)	`Picker.cs`, `PickerTests.cs`	Added test for Replace action
4	gpt-5.4 (gemini unavailable)	Fix `GetSelectedIndex()` directly: remove stale-index fallback, return -1 when SelectedItem not found; update mutation callers to always resync	✅ PASS (49/49)	`Picker.cs`	Fixes root cause at source method
5	cross-pollination (gpt-5.3-codex)	Index-driven mutations: SelectedIndex as source of truth; no SelectedItem lookup during Add/Remove	❌ FAIL (hang)	`Picker.cs`	Re-entrant SelectedIndex change causing infinite loop
PR	PR #34299	Add `GetSelectedIndexForCollectionMutation()` returning -1 when item not found; original `GetSelectedIndex()` unchanged	✅ PASSED (Gate)	`Picker.cs`, `PickerTests.cs`	Original PR — adds test coverage

Cross-Pollination

Model	Round	New Ideas?	Details
claude-opus-4.6	2	No	NO NEW IDEAS
gpt-5.3-codex	2	Yes	Index-driven approach → tested as Attempt 5 → ❌ FAIL
claude-sonnet-4.6	2	No	NO NEW IDEAS

Exhausted: Yes — all 4 models queried, no further new ideas

Selected Fix: PR's fix — Reason: The PR's GetSelectedIndexForCollectionMutation() approach is the safest for a servicing/bug-fix context. It minimally scopes the change to mutation contexts only, preserves the existing GetSelectedIndex() behavior for all other callers, and includes good test coverage. Attempts 1 and 4 are simpler alternatives, but the PR's approach makes the intent explicit and is safest as a conservative fix. Attempt 2 (ClampSelectedIndex) is elegant but has subtle risks if called outside ItemsSource context.

📋 Report — Final Recommendation

✅ Final Recommendation: APPROVE

Phase Status

Phase	Status	Notes
Pre-Flight	✅ COMPLETE	Issue #33307, unit tests, 2 files changed
Gate	✅ PASSED	Android — tests fail without fix, pass with fix
Try-Fix	✅ COMPLETE	5 attempts (4 passing, 1 failing); cross-pollination exhausted
Report	✅ COMPLETE

Summary

PR #34299 fixes a real, verified bug in Picker where removing the selected item from ItemsSource caused index-based (stale) selection instead of clearing selection. The fix is minimal, well-scoped, and backed by 3 new unit tests. Multi-model exploration confirmed the fix is sound — 4 independent approaches all passed, and the PR's implementation is among the safest choices for a servicing fix.

Selected Fix: PR's fix (GetSelectedIndexForCollectionMutation()) — conservative, well-scoped, doesn't break existing callers of GetSelectedIndex().

Root Cause

GetSelectedIndex() fell back to returning the previous SelectedIndex when SelectedItem was no longer found in the collection (return newIndex >= 0 ? newIndex : SelectedIndex). This caused collection mutations (remove, reset) to preserve a stale index pointing to whatever item now occupies that position, instead of clearing the selection to signal "no item selected."

Fix Quality

Strengths:

Scoped to mutation paths only (RemoveItems, AddItems, ResetItems) via new GetSelectedIndexForCollectionMutation() — preserves all existing GetSelectedIndex() behavior
Covers the right cases: clears selection when selected item removed, preserves when unrelated item removed, preserves when item inserted before/after selection
3 new unit tests cover the new behavior and prevent regressions
Updated TestItemsSourceCollectionChangedRemoveAtEndSelected test expectations are correct (selected item removed → selection cleared, not "move to last item")

Minor concerns (non-blocking):

GetSelectedIndexForCollectionMutation() and GetSelectedIndex() are nearly identical with subtle fallback differences. The PR author acknowledged this and chose to keep them separate for safety. This is defensible for a bug fix. A future refactor could unify them with a parameter.
PR description's "Root Cause" section mentions modifying GetSelectedIndex() directly, but the actual implementation uses a new method — mismatch noted by Copilot PR reviewer, acknowledged but not yet updated. Recommend updating the description before merge.
kubaflo's device/UI test runs should be confirmed passing before merge.

kubaflo · 2026-03-22T16:03:07Z

I'm pretty sure this PR will regress some other aspects of the picker

kubaflo · 2026-03-22T16:03:22Z

/azp run maui-pr-uitests

azure-pipelines · 2026-03-22T16:03:35Z

Azure Pipelines successfully started running 1 pipeline(s).

kubaflo · 2026-03-22T16:03:35Z

/azp run maui-pr-devicetests

azure-pipelines · 2026-03-22T16:03:47Z

Azure Pipelines successfully started running 1 pipeline(s).

- Avoid modifying shared GetSelectedIndex behavior - Update selection only during collection mutations (add/remove/reset) - Ensure SelectedIndex is reset when SelectedItem is no longer present - Prevent stale or incorrect selection after ItemsSource changes

jpd21122012 · 2026-03-23T03:17:05Z

I'm pretty sure this PR will regress some other aspects of the picker

Thanks for the feedback!

I’ve reworked the fix to avoid modifying the shared GetSelectedIndex logic.

Instead, the selection is now updated only during collection mutations (add/remove/reset). This ensures that when the selected item is removed from the ItemsSource, the Picker does not fall back to a stale index, while keeping existing selection behavior intact for other scenarios.

I also verified this against multiple cases (item removal, insertions, reordering, and binding scenarios) to ensure no regressions.

Let me know if you’d like me to add test coverage for this

Copilot

Pull request overview

Fixes Picker selection consistency when ItemsSource mutates so selection is based on the selected object identity (and cleared when the selected object is removed), rather than accidentally “sticking” to an index that now points at a different item.

Changes:

Introduces GetSelectedIndexForCollectionMutation() to compute selection index from SelectedItem without falling back to the previous SelectedIndex when the item is missing.
Updates AddItems, RemoveItems, and ResetItems to use the new selection computation for collection-change scenarios.
Explicitly clears selection (ClampSelectedIndex(-1)) when a removal causes SelectedItem to no longer exist in the backing collection.

src/Controls/src/Core/Picker/Picker.cs

- Verify selection is cleared when selected item is removed - Verify selection is preserved when non-selected items are removed - Verify selection remains consistent during insert and reorder scenarios

kubaflo

TestItemsSourceCollectionChangedRemoveAtEndSelected is failing

Selection should be cleared when the selected item is removed from the ItemsSource. Updated test to expect SelectedIndex = -1 and SelectedItem = null.

jpd21122012 · 2026-03-26T16:43:50Z

TestItemsSourceCollectionChangedRemoveAtEndSelected is failing

I investigated the failure in TestItemsSourceCollectionChangedRemoveAtEndSelected and the issue was with the test expectation, not the Picker behavior.

The test was asserting that after removing the selected item from the ItemsSource, the selection should move to the last remaining item. That leads to an inconsistent state because the selected item no longer exists in the source.

I updated the test to reflect the correct behavior:

SelectedIndex should be -1
SelectedItem should be null

After correcting the expectation, the tests pass.

MauiBot · 2026-04-01T19:15:16Z

🚦 Gate - Test Before and After Fix

📊 Expand Full Gate — db83806 · [Picker] Fix test expectation when removing selected item

Gate Result: ✅ PASSED

Platform: ANDROID · Base: main · Merge base: 794a9fa6

Test	Without Fix (expect FAIL)	With Fix (expect PASS)
🧪 PickerTests `PickerTests`	✅ FAIL — 106s	✅ PASS — 66s

🔴 Without fix — 🧪 PickerTests: FAIL ✅ · 106s

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Test run for /home/vsts/work/1/s/artifacts/bin/Controls.Core.UnitTests/Debug/net10.0/Microsoft.Maui.Controls.Core.UnitTests.dll (.NETCoreApp,Version=v10.0)
VSTest version 18.0.1 (x64)

Starting test execution, please wait...
A total of 1 test files matched the specified pattern.
[xUnit.net 00:00:00.00] xUnit.net VSTest Adapter v2.8.2+699d445a1a (64-bit .NET 10.0.0)
[xUnit.net 00:00:00.16]   Discovering: Microsoft.Maui.Controls.Core.UnitTests
[xUnit.net 00:00:01.25]   Discovered:  Microsoft.Maui.Controls.Core.UnitTests
[xUnit.net 00:00:01.26]   Starting:    Microsoft.Maui.Controls.Core.UnitTests
  Passed PickerRetainsSelectionWhenUnselectedItemIsRemovedFromItemsSource [14 ms]
  Passed NullItemReturnsEmptyStringFromInterface [1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 0, insertNames: ["George", "Pete"]) [9 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 2, insertNames: ["George"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 1, insertNames: ["George"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 1, insertNames: ["George", "Pete"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 2, insertNames: ["George", "Pete"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 3, insertNames: ["George"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 0, insertNames: ["George"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 3, insertNames: ["George", "Pete"]) [< 1 ms]
  Passed TestSelectedIndexAssignedItemsSourceCollectionChangedInsert [2 ms]
  Passed TestItemsSourceCollectionChangedReAssign [6 ms]
  Passed TestItemsSourceCollectionOfStrings [< 1 ms]
  Passed PickerRetainsSelectionAfterInsertReorderingItemsSource [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 1, removeCount: 2, selectedItemPreserved: False) [4 ms]
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 2, removeCount: 1, selectedItemPreserved: True) [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 0, removeCount: 2, selectedItemPreserved: False) [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 1, removeCount: 1, selectedItemPreserved: False) [< 1 ms]
[xUnit.net 00:00:01.39]       Assert.Equal() Failure: Values differ
[xUnit.net 00:00:01.39]       Expected: -1
[xUnit.net 00:00:01.39]       Actual:   1
[xUnit.net 00:00:01.39]       Stack Trace:
[xUnit.net 00:00:01.39]         /_/src/Controls/tests/Core.UnitTests/PickerTests.cs(876,0): at Microsoft.Maui.Controls.Core.UnitTests.PickerTests.PickerClearsSelectionWhenSelectedItemIsRemovedFromItemsSource()
[xUnit.net 00:00:01.39]            at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
[xUnit.net 00:00:01.39]            at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 0, removeCount: 1, selectedItemPreserved: True) [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 2, removeCount: 2, selectedItemPreserved: True) [< 1 ms]
  Passed TestSelectedIndexChangedOnCollectionShrink [1 ms]
  Passed TestSelectedIndexOutOfRangeUpdatesSelectedItem [< 1 ms]
  Passed TestDisplayConverter [< 1 ms]
  Passed PickerPreservesSelectedItemAfterRemovingItemBeforeSelection [< 1 ms]
  Passed TestSelectedIndexInRange [< 1 ms]
  Failed PickerClearsSelectionWhenSelectedItemIsRemovedFromItemsSource [2 ms]
  Error Message:
   Assert.Equal() Failure: Values differ
Expected: -1
Actual:   1
  Stack Trace:
     at Microsoft.Maui.Controls.Core.UnitTests.PickerTests.PickerClearsSelectionWhenSelectedItemIsRemovedFromItemsSource() in /_/src/Controls/tests/Core.UnitTests/PickerTests.cs:line 876
   at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
   at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)
  Passed TestSelectedItemSet [3 ms]
[xUnit.net 00:00:01.39]       Assert.Equal() Failure: Values differ
[xUnit.net 00:00:01.39]       Expected: -1
[xUnit.net 00:00:01.39]       Actual:   1
[xUnit.net 00:00:01.39]       Stack Trace:
[xUnit.net 00:00:01.39]         /_/src/Controls/tests/Core.UnitTests/PickerTests.cs(475,0): at Microsoft.Maui.Controls.Core.UnitTests.PickerTests.TestItemsSourceCollectionChangedRemoveAtEndSelected(Int32 removeCount)
[xUnit.net 00:00:01.39]            at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
[xUnit.net 00:00:01.39]            at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
[xUnit.net 00:00:01.39]       Assert.Equal() Failure: Values differ
[xUnit.net 00:00:01.39]       Expected: -1
[xUnit.net 00:00:01.39]       Actual:   2
[xUnit.net 00:00:01.39]       Stack Trace:
[xUnit.net 00:00:01.39]         /_/src/Controls/tests/Core.UnitTests/PickerTests.cs(475,0): at Microsoft.Maui.Controls.Core.UnitTests.PickerTests.TestItemsSourceCollectionChangedRemoveAtEndSelected(Int32 removeCount)
[xUnit.net 00:00:01.39]            at InvokeStub_PickerTests.TestItemsSourceCollectionChangedRemoveAtEndSelected(Object, Span`1)
[xUnit.net 00:00:01.39]            at System.Reflection.MethodBaseInvoker.InvokeWithOneArg(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
[xUnit.net 00:00:01.39]     PickerClearsSelectionWhenSelectedItemIsRemovedFromItemsSource [FAIL]
[xUnit.net 00:00:01.39]     TestItemsSourceCollectionChangedRemoveAtEndSelected(removeCount: 2) [FAIL]
[xUnit.net 00:00:01.39]     TestItemsSourceCollectionChangedRemoveAtEndSelected(removeCount: 1) [FAIL]
  Passed TestSelectedIndexAssignedItemsSourceCollectionChangedReAssign [< 1 ms]
  Passed TestSelectedIndexAssignedItemsSourceCollectionChangedClear [1 ms]
  Passed TestItemsSourceCollectionChangedClear [< 1 ms]
  Passed TestSelectedIndexInRangeDefaultSelectedIndex [< 1 ms]
  Failed TestItemsSourceCollectionChangedRemoveAtEndSelected(removeCount: 2) [< 1 ms]
  Error Message:
   Assert.Equal() Failure: Values differ
Expected: -1
Actual:   1
  Stack Trace:
     at Microsoft.Maui.Controls.Core.UnitTests.PickerTests.TestItemsSourceCollectionChangedRemoveAtEndSelected(Int32 removeCount) in /_/src/Controls/tests/Core.UnitTests/PickerTests.cs:line 475
   at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
   at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
  Failed TestItemsSourceCollectionChangedRemoveAtEndSelected(removeCount: 1) [< 1 ms]
  Error Message:
   Assert.Equal() Failure: Values differ
Expected: -1
Actual:   2
  Stack Trace:
     at Microsoft.Maui.Controls.Core.UnitTests.PickerTests.TestItemsSourceCollectionChangedRemoveAtEndSelected(Int32 removeCount) in /_/src/Controls/tests/Core.UnitTests/PickerTests.cs:line 475
   at InvokeStub_PickerTests.TestItemsSourceCollectionChangedRemoveAtEndSelected(Object, Span`1)
   at System.Reflection.MethodBaseInvoker.InvokeWithOneArg(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
  Passed TestSelectedItemChangeSelectedIndex [< 1 ms]
  Passed TestNestedDisplayMemberPathExpression [< 1 ms]
  Passed TestSetItemsSourceProperty [1 ms]
  Passed PickerPreservesSelectedItemAfterInsertingItemBeforeSelection [< 1 ms]
  Passed TestItemsSourceCollectionChangedAppend [< 1 ms]
  Passed SettingSelectedIndexUpdatesSelectedItem [2 ms]
  Passed TestSelectedItemAssignedItemsSourceCollectionChangedRemove [< 1 ms]
  Passed ThrowsWhenModifyingItemsIfItemsSourceIsSet [< 1 ms]
  Passed TestItemsSourceEnums [3 ms]
  Passed TestEmptyCollectionResetItems [< 1 ms]
  Passed TestSetSelectedIndexOnNullRows [< 1 ms]
  Passed TestSelectedIndexAssignedItemsSourceCollectionChangedAppend [< 1 ms]
[xUnit.net 00:00:01.40]   Finished:    Microsoft.Maui.Controls.Core.UnitTests
  Passed TestSelectedItemDefault [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsert [< 1 ms]
  Passed TestUnsubscribeINotifyCollectionChanged [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemove [< 1 ms]

Test Run Failed.
Total tests: 49
     Passed: 46
     Failed: 3
 Total time: 1.8646 Seconds

🟢 With fix — 🧪 PickerTests: PASS ✅ · 66s

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Test run for /home/vsts/work/1/s/artifacts/bin/Controls.Core.UnitTests/Debug/net10.0/Microsoft.Maui.Controls.Core.UnitTests.dll (.NETCoreApp,Version=v10.0)
VSTest version 18.0.1 (x64)

Starting test execution, please wait...
A total of 1 test files matched the specified pattern.
[xUnit.net 00:00:00.00] xUnit.net VSTest Adapter v2.8.2+699d445a1a (64-bit .NET 10.0.0)
[xUnit.net 00:00:00.37]   Discovering: Microsoft.Maui.Controls.Core.UnitTests
[xUnit.net 00:00:02.96]   Discovered:  Microsoft.Maui.Controls.Core.UnitTests
[xUnit.net 00:00:02.97]   Starting:    Microsoft.Maui.Controls.Core.UnitTests
  Passed PickerRetainsSelectionWhenUnselectedItemIsRemovedFromItemsSource [22 ms]
  Passed NullItemReturnsEmptyStringFromInterface [1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 0, insertNames: ["George", "Pete"]) [15 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 2, insertNames: ["George"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 1, insertNames: ["George"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 1, insertNames: ["George", "Pete"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 2, insertNames: ["George", "Pete"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 3, insertNames: ["George"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 0, insertNames: ["George"]) [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsertBeforeSelected(insertionIndex: 3, insertNames: ["George", "Pete"]) [< 1 ms]
  Passed TestSelectedIndexAssignedItemsSourceCollectionChangedInsert [2 ms]
  Passed TestItemsSourceCollectionChangedReAssign [6 ms]
  Passed TestItemsSourceCollectionOfStrings [< 1 ms]
  Passed PickerRetainsSelectionAfterInsertReorderingItemsSource [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 1, removeCount: 2, selectedItemPreserved: False) [2 ms]
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 2, removeCount: 1, selectedItemPreserved: True) [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 0, removeCount: 2, selectedItemPreserved: False) [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 1, removeCount: 1, selectedItemPreserved: False) [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 0, removeCount: 1, selectedItemPreserved: True) [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemoveBeforeSelected(removeIndex: 2, removeCount: 2, selectedItemPreserved: True) [< 1 ms]
  Passed TestSelectedIndexChangedOnCollectionShrink [1 ms]
  Passed TestSelectedIndexOutOfRangeUpdatesSelectedItem [1 ms]
  Passed TestDisplayConverter [1 ms]
  Passed PickerPreservesSelectedItemAfterRemovingItemBeforeSelection [< 1 ms]
  Passed TestSelectedIndexInRange [< 1 ms]
  Passed PickerClearsSelectionWhenSelectedItemIsRemovedFromItemsSource [< 1 ms]
  Passed TestSelectedItemSet [3 ms]
  Passed TestSelectedIndexAssignedItemsSourceCollectionChangedReAssign [< 1 ms]
  Passed TestSelectedIndexAssignedItemsSourceCollectionChangedClear [1 ms]
  Passed TestItemsSourceCollectionChangedClear [< 1 ms]
  Passed TestSelectedIndexInRangeDefaultSelectedIndex [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemoveAtEndSelected(removeCount: 2) [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemoveAtEndSelected(removeCount: 1) [< 1 ms]
  Passed TestSelectedItemChangeSelectedIndex [< 1 ms]
  Passed TestNestedDisplayMemberPathExpression [< 1 ms]
  Passed TestSetItemsSourceProperty [1 ms]
  Passed PickerPreservesSelectedItemAfterInsertingItemBeforeSelection [< 1 ms]
  Passed TestItemsSourceCollectionChangedAppend [< 1 ms]
  Passed SettingSelectedIndexUpdatesSelectedItem [3 ms]
  Passed TestSelectedItemAssignedItemsSourceCollectionChangedRemove [< 1 ms]
  Passed ThrowsWhenModifyingItemsIfItemsSourceIsSet [< 1 ms]
  Passed TestItemsSourceEnums [2 ms]
  Passed TestEmptyCollectionResetItems [< 1 ms]
  Passed TestSetSelectedIndexOnNullRows [< 1 ms]
  Passed TestSelectedIndexAssignedItemsSourceCollectionChangedAppend [< 1 ms]
[xUnit.net 00:00:03.11]   Finished:    Microsoft.Maui.Controls.Core.UnitTests
  Passed TestSelectedItemDefault [< 1 ms]
  Passed TestItemsSourceCollectionChangedInsert [< 1 ms]
  Passed TestUnsubscribeINotifyCollectionChanged [< 1 ms]
  Passed TestItemsSourceCollectionChangedRemove [< 1 ms]

Test Run Successful.
Total tests: 49
     Passed: 49
 Total time: 4.2071 Seconds

📁 Fix files reverted (2 files)

eng/pipelines/ci-copilot.yml
src/Controls/src/Core/Picker/Picker.cs

jpd21122012 · 2026-04-06T15:31:57Z

Hi, just following up on this PR.

I reworked the fix to scope the behavior specifically to collection mutations, avoiding changes to the shared GetSelectedIndex logic.

I also added regression tests and validated the following scenarios:

Removing the selected item → selection is cleared
Removing a non-selected item → selection is preserved
Inserting items before/after the selected item → selection remains correct
Reordering items → selection remains consistent based on SelectedItem identity

The goal is to ensure the fix addresses the issue without impacting existing selection behavior.

Let me know if there are any additional scenarios you’d like me to cover

kubaflo · 2026-04-07T09:18:49Z

/azp run maui-pr-uitests

azure-pipelines · 2026-04-07T09:18:56Z

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azure-pipelines · 2026-04-07T09:20:07Z

Azure Pipelines successfully started running 1 pipeline(s).

kubaflo · 2026-04-07T09:20:31Z

/azp run maui-pr-devicetests

azure-pipelines · 2026-04-07T09:20:46Z

Azure Pipelines successfully started running 1 pipeline(s).

kubaflo · 2026-04-07T09:23:01Z

🟢 .NET MAUI Review - Approved

Expand Full Review - db83806 - Fix Picker selection when SelectedItem is removed from ItemsSource

Code Review — PR #34299

Independent Assessment

What this changes: Introduces identity-based selection tracking for the Picker control during ItemsSource collection mutations. A new method GetSelectedIndexForCollectionMutation() resolves the selected item's index without falling back to the previous SelectedIndex when the item is no longer in the collection. RemoveItems now detects when the selected item has been removed (index == -1 && SelectedItem != null) and clears the selection. ResetItems also uses the new method so a full collection reset properly clears selection when the selected item is gone.

Inferred motivation: The old GetSelectedIndex() fell back to SelectedIndex when SelectedItem was not found in the collection, causing the Picker to silently select a different item occupying the old index position after a removal. This is confusing UX — users expect either the same item to remain selected, or selection to be cleared.

Reconciliation with PR Narrative

Author claims: Fixes #33307 — when a selected item is removed from ItemsSource, the Picker should clear selection instead of selecting whatever item now occupies the old index.

Agreement: The code matches this description exactly. The root cause analysis (fallback to stale SelectedIndex in GetSelectedIndex()) is correct. The fix is targeted and preserves the original GetSelectedIndex() for the OnItemsCollectionChanged path (direct Items manipulation), which is appropriate.

Findings

💡 Suggestion — Add a test for the `ResetItems` path

The PR changes ResetItems() from ClampSelectedIndex(SelectedIndex) to ClampSelectedIndex(GetSelectedIndexForCollectionMutation()). This is an important behavioral change (a full collection reset now clears selection if the selected item is absent), but there is no test that exercises this path. Consider adding a test like:

[Fact]
public void PickerClearsSelectionWhenItemsSourceIsReplacedWithoutSelectedItem()
{
    var items = new ObservableCollection<string> { "A", "B", "C" };
    var picker = new Picker { ItemsSource = items, SelectedItem = "B" };
    
    // Replace ItemsSource entirely — "B" is not in the new list
    picker.ItemsSource = new ObservableCollection<string> { "X", "Y", "Z" };
    
    Assert.Equal(-1, picker.SelectedIndex);
    Assert.Null(picker.SelectedItem);
}

💡 Suggestion — Consider a test for `Replace`/`Move` actions routing through `ResetItems`

The CollectionChanged handler routes Move, Replace, and Reset actions through ResetItems(). A test that replaces a selected item in-place (e.g., items[1] = "NewItem") would verify this path too.

Devil's Advocate

Could clearing selection on removal break existing apps? Theoretically, apps that relied on "select the item at the same index after removal" would see different behavior. However, that old behavior was essentially a bug — silently selecting a different item is far worse than clearing selection. The new behavior is consistent with standard UI framework semantics (WPF, WinUI ComboBox all clear selection when the selected item is removed).
Is the two-method split (GetSelectedIndex / GetSelectedIndexForCollectionMutation) the right design? The alternative would be adding a parameter to GetSelectedIndex. But the split is clearer — GetSelectedIndex retains its existing semantics for the OnItemsCollectionChanged path, and the new method has a descriptive (if verbose) name that communicates its purpose. This is acceptable.
CI status: The previous maui-pr run shows a macOS Debug build failure, but all Helix unit tests (Debug and Release) passed, confirming the test changes compile and run correctly. A new CI run is in progress. The macOS Debug failure appears infrastructure-related (not caused by this PR's changes, since the code is entirely cross-platform shared code that built successfully on Windows in both Debug and Release).

Verdict: LGTM

Confidence: high
Summary: The fix correctly transitions from index-based to identity-based selection tracking during collection mutations. The new RemoveItems logic properly detects and clears selection when the selected item is removed. Tests are well-structured, covering the key scenarios (removal of selected item, removal of unselected item, and insert reordering). Two minor suggestions for additional test coverage of the ResetItems and Replace paths.

kubaflo

This test is failing PickerShouldNotCrashWhenSelectedIndexExceedsItemsSourceCount

Refine logic to clear SelectedItem only if it was actually removed from the collection, using LINQ's Contains for accuracy. Adds System.Linq import to support this check.

jpd21122012 · 2026-04-12T21:37:53Z

This test is failing PickerShouldNotCrashWhenSelectedIndexExceedsItemsSourceCount

Thanks for the feedback!

I updated the implementation to only clear the selection when the SelectedItem is explicitly part of the removed items, instead of relying on index resolution.

I ran the full PickerTests suite (49 tests), including the scenarios around collection mutations (insert/remove/reorder), and all tests are passing with no regressions.

This ensures the fix addresses the issue while preserving existing selection behavior

kubaflo · 2026-04-12T22:22:25Z

/azp run maui-pr-uitests , maui-pr-devicetests

azure-pipelines · 2026-04-12T22:22:38Z

Azure Pipelines successfully started running 2 pipeline(s).

Fix Picker selection when SelectedItem is removed from ItemsSource

a1bf3f5

dotnet-policy-service bot added the community ✨ Community Contribution label Mar 2, 2026

MauiBot added s/agent-changes-requested AI agent recommends changes - found a better alternative or issues s/agent-fix-win AI found a better alternative fix than the PR s/agent-reviewed PR was reviewed by AI agent workflow (full 4-phase review) labels Mar 22, 2026

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CI UItests failure System.TimeoutException : Timed out waiting for element... #33220

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System.TimeoutException #33245

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Copilot AI review requested due to automatic review settings March 23, 2026 03:16

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Add regression tests for Picker selection during ItemsSource mutations

12e5a67

- Verify selection is cleared when selected item is removed - Verify selection is preserved when non-selected items are removed - Verify selection remains consistent during insert and reorder scenarios

MauiBot added s/agent-review-incomplete AI agent could not complete all phases (blocker, timeout, error) and removed s/agent-changes-requested AI agent recommends changes - found a better alternative or issues labels Mar 24, 2026

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[Picker] Fix test expectation when removing selected item

db83806

Selection should be cleared when the selected item is removed from the ItemsSource. Updated test to expect SelectedIndex = -1 and SelectedItem = null.

jpd21122012 requested a review from kubaflo April 1, 2026 17:18

MauiBot removed the s/agent-review-incomplete AI agent could not complete all phases (blocker, timeout, error) label Apr 1, 2026

MauiBot added s/agent-approved AI agent recommends approval - PR fix is correct and optimal s/agent-fix-pr-picked AI could not beat the PR fix - PR is the best among all candidates and removed s/agent-fix-win AI found a better alternative fix than the PR labels Apr 1, 2026

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[PR Review Queue] PR Review Queue — April 5, 2026 #34820

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[PR Review Queue] PR Review Queue — April 5, 2026 #34821

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[PR Review Queue] PR Review Queue — April 5, 2026 #34822

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kubaflo requested changes Apr 10, 2026

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Improve Picker selection clearing on item removal

1f8782c

Refine logic to clear SelectedItem only if it was actually removed from the collection, using LINQ's Contains for accuracy. Adds System.Linq import to support this check.

jpd21122012 requested a review from kubaflo April 12, 2026 21:38

Conversation

jpd21122012 commented Mar 2, 2026

Description of Change

Root Cause

Fix

Verified Scenarios

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🤖 AI Summary

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✅ Final Recommendation: APPROVE

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🚦 Gate - Test Before and After Fix

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kubaflo commented Apr 7, 2026

🟢 .NET MAUI Review - Approved

Code Review — PR #34299

Independent Assessment

Reconciliation with PR Narrative

Findings

💡 Suggestion — Add a test for the ResetItems path

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💡 Suggestion — Add a test for the `ResetItems` path

💡 Suggestion — Consider a test for `Replace`/`Move` actions routing through `ResetItems`