Fix ListView is in virtual mode #3963

SergeySmirnov-Akvelon · 2020-09-21T14:18:59Z

Proposed changes

implemented using SelectedIndices instead of SelectedItems when getting Accessible Objects, because SelectedIndices property is available in any mode (virtual and default);
added a check for methods from ListViewGroup that the ListView is not in virtual mode, since ListViewGroups are not supported for virtual mode;
replaced "groups.Count > 0" condition on "GroupsEnabled" in logic for navigation on ListView by keyboard. Together with the "groups.Count > 0" condition, it also checks that Groups is displayed and ListView is in default (not virtual) mode;
updated logic for "ExpandCollapseState" property ;
added the condition that if a ListViewItem is located in a ListViewGroup and this ListViewGroup is collapsed we return empty rectangle otherwise we call old logic for getting of rectangle
added check that the index should be greater than -1 and less than the number of Items in the ListView. If check is failed then we will return false, otherwise we will get the ListViewItem using index and check "Selected" property;

Customer Impact

ListView in virtual mode
During implementation of accessible objects for ListView we started to use "SelectedItems" properties for getting of required items. Unfortunately, "SelectedItems", "CheckedItems" and partially "Items" properties are not available when the ListView is in virtual mode. If trying to get any properties/methods from "SelecedItems", "CheckedItems" or get enumerator of "Items" then ListView throws IOE in virtual mode. As result we got an exceptions when tried to do any UI action when ListView is in virtual mode.

After fixing issue with ListView in a virtual mode, it is again available for navigation and UI interaction:

ListViewGroup.ListViewGroupAccessibleObject.ExpandCollapseState
The ExpandCollapseState is not valid for non-collapsible ListViewGroup. User sees that such group has "Collapsed" state although the group cannot be collapsed:

After fixing, ExpandCollapseState is valid for non-collapsible ListViewGroup:

ListViewItem.ListViewItemAccessibleObject.Bounds
If a ListViewItem is in a collapsed ListViewGroup and user tries to selects it in Inspector then user will see exception:

After fixing, user can see data about ListViewItem in a collapsed ListViewGroup without application exception:

Regression?

Yes

Risk

Minimal

Test methodology

Manually
Unit tests
CTI

Test environment(s)

Microsoft Windows [Version 10.0.19041.388]
NET Core 5.0.100-rc.1.20420.14

Accessibility Testing

Narrator
Inspector

Microsoft Reviewers: Open in CodeFlow

vladimir-krestov

Viewed

src/System.Windows.Forms/src/System/Windows/Forms/ListView.ListViewAccessibleObject.cs

src/System.Windows.Forms/src/System/Windows/Forms/ListViewItem.ListViewItemAccessibleObject.cs

codecov · 2020-09-25T15:00:55Z

Codecov Report

Merging #3963 into release/5.0 will decrease coverage by 30.79424%.
The diff coverage is 83.07692%.

@@                  Coverage Diff                   @@
##           release/5.0       #3963          +/-   ##
======================================================
- Coverage     67.87270%   37.07846%   -30.79424%     
======================================================
  Files             1416         924         -492     
  Lines           507889      250984      -256905     
  Branches         41298       36986        -4312     
======================================================
- Hits            344718       93061      -251657     
+ Misses          156983      152461        -4522     
+ Partials          6188        5462         -726

Flag	Coverage Δ
#Debug	`37.07846% <83.07692%> (-30.79424%)`	⬇️
#production	`37.07846% <83.07692%> (+0.15865%)`	⬆️
#test	`?`

Flags with carried forward coverage won't be shown. Click here to find out more.

src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/ListViewTests.cs

src/System.Windows.Forms/src/System/Windows/Forms/ListView.ListViewAccessibleObject.cs

...System.Windows.Forms/src/System/Windows/Forms/ListViewGroup.ListViewGroupAccessibleObject.cs

RussKie · 2020-09-28T04:47:42Z

...System.Windows.Forms/src/System/Windows/Forms/ListViewGroup.ListViewGroupAccessibleObject.cs

-                _owningListView = owningGroup.ListView ?? throw new InvalidOperationException(nameof(owningGroup.ListView));
+                _owningListView = owningGroup.ListView
+                    ?? (owningGroup.Items.Count > 0 && _owningGroup.Items[0].ListView != null
+                        ? _owningGroup.Items[0].ListView
+                        : throw new InvalidOperationException(nameof(owningGroup.ListView)));


Suspected bug, tracked across #3987 and #4001

RussKie · 2020-09-28T05:38:03Z

src/System.Windows.Forms/src/System/Windows/Forms/ListViewItem.ListViewItemAccessibleObject.cs

@@ -23,7 +23,7 @@ internal class ListViewItemAccessibleObject : AccessibleObject
            public ListViewItemAccessibleObject(ListViewItem owningItem, ListViewGroup? owningGroup)
            {
                _owningItem = owningItem ?? throw new ArgumentNullException(nameof(owningItem));
-                _owningListView = owningItem.ListView ?? throw new InvalidOperationException(nameof(owningItem.ListView));
+                _owningListView = owningItem.ListView ?? owningGroup?.ListView ?? throw new InvalidOperationException(nameof(owningItem.ListView));


Suspected bug, tracked across #3987 and #4001

During implementation of accessible objects for ListView we started to use SelectedItems property for getting of required items. Unfortunately, this property is not available when the ListView is in virtual mode. As result we got an exceptions when tried to do any UI action when ListView is in virtual mode. As a fix, we implemented using SelectedIndices instead of SelectedItems when getting Accessible Objects, because SelectedIndices property is available in any mode. Also we added a check for methods in ListViewGroup that the ListView is not in virtual mode, since ListViewGroups are not supported for virtual mode. Besides we replaced "groups.Count > 0" condition on "GroupsEnabled" in logic for navigation on ListView by keyboard. Together with the "groups.Count > 0" condition, it also checks that Groups is displayed and ListView is in default (not virtual) mode

…roperty Original implementation for ExpandCollapseState is not valid because ListViewGroupCollapsedState can have Default (Non-collapsible) state. In this case user will see that group has "Collapsed" state, although the group does not support collapsing. As result logic for ExpandCollapseState property was updated. If group has "Collapsed" state then we return "Collapsed" else we return "Expanded" for "Expanded" and "Default" states

If a ListViewItem is in a collapsed ListViewGroup and we try to select it in Inspector then we get exception. It happens because during trying to get "Bounds" property we send a "GETITEMRECT" message to NativeControl and receive empty result. To avoid this issue, we added the condition that if a ListViewItem is located in a ListViewGroup and this ListViewGroup is collapsed we return empty rectangle otherwise we call old logic for getting of rectangle

The "SelectedIndexies.Contains" method tries to get ListViewItem using the index from parameter and checks "Selected" property for this ListViewItem. If we close the dialog that contains ListView then ListView is still available to us in the inspector, but ListViewItem will have index with "-1" value. As result if we call "SelectedIndexies.Contains" method for ListViewItem with such index then we get an exception. As a fix we added check that the index should be greater than -1 and less than the number of Items in the ListView. If check is failed then we will return false, otherwise we will get the ListViewItem using index and check "Selected" property

Related to PR dotnet#3963 and PR dotnet#3224 Fix keyboard Narrator announcing the check/uncheck state of ListView item when enabling ListView CheckBoxes property Fixes Issue dotnet#4029

SergeySmirnov-Akvelon requested a review from a team as a code owner September 21, 2020 14:18

ghost assigned SergeySmirnov-Akvelon Sep 21, 2020

SergeySmirnov-Akvelon marked this pull request as draft September 21, 2020 14:20

SergeySmirnov-Akvelon changed the title ~~Fixing issue with ListView in virtual mode~~ Fixing exceptions in ListView is in virtual mode Sep 21, 2020

RussKie added this to the 5.0 RC2 milestone Sep 21, 2020

RussKie added Servicing-consider .NET Shiproom label indicating a PR seeks to enter into a branch under Tell-Mode criteria tenet-accessibility MAS violation, UIA issue; problems with accessibility standards 🪲 bug Product bug (most likely) labels Sep 21, 2020

RussKie linked an issue Sep 22, 2020 that may be closed by this pull request

ListView is in virtual mode throws IOE #3962

Closed

vladimir-krestov reviewed Sep 22, 2020

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RussKie self-assigned this Sep 23, 2020

SergeySmirnov-Akvelon force-pushed the Issue-3962_ListView_is_in_virtual_mode_throws_exception branch 2 times, most recently from d1dad32 to 562404f Compare September 23, 2020 07:00

RussKie changed the title ~~Fixing exceptions in ListView is in virtual mode~~ Fix ListView is in virtual mode Sep 23, 2020

SergeySmirnov-Akvelon force-pushed the Issue-3962_ListView_is_in_virtual_mode_throws_exception branch from 97b4697 to fa62c0d Compare September 23, 2020 19:28

RussKie added Servicing-approved .NET Shiproom approved the PR for merge and removed Servicing-consider .NET Shiproom label indicating a PR seeks to enter into a branch under Tell-Mode criteria labels Sep 24, 2020

Tanya-Solyanik reviewed Sep 25, 2020

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SergeySmirnov-Akvelon force-pushed the Issue-3962_ListView_is_in_virtual_mode_throws_exception branch 4 times, most recently from 3bd1c21 to 85bcea6 Compare September 25, 2020 14:59

SergeySmirnov-Akvelon force-pushed the Issue-3962_ListView_is_in_virtual_mode_throws_exception branch from 85bcea6 to efda3fd Compare September 25, 2020 15:13

This was referenced Sep 25, 2020

Test failures via timeline in Roslyn jaredpar/runfo#37

Closed

Test failures via timeline in Roslyn jaredpar/runfo#38

Closed

SergeySmirnov-Akvelon force-pushed the Issue-3962_ListView_is_in_virtual_mode_throws_exception branch from efda3fd to e8db5db Compare September 25, 2020 16:06

Tanya-Solyanik reviewed Sep 27, 2020

View reviewed changes

src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/ListViewTests.cs Outdated Show resolved Hide resolved

RussKie changed the base branch from release/5.0-rc2 to release/5.0 September 28, 2020 02:21

RussKie removed this from the 5.0 RC2 milestone Sep 28, 2020

RussKie added this to the 5.0 GA milestone Sep 28, 2020

RussKie force-pushed the Issue-3962_ListView_is_in_virtual_mode_throws_exception branch from ad29a5d to 2a42c89 Compare September 28, 2020 04:08

RussKie reviewed Sep 28, 2020

View reviewed changes

RussKie marked this pull request as ready for review September 28, 2020 22:34

SergeySmirnov-Akvelon force-pushed the Issue-3962_ListView_is_in_virtual_mode_throws_exception branch 2 times, most recently from b858c97 to 3c65c95 Compare September 29, 2020 12:49

SergeySmirnov-Akvelon added 5 commits September 29, 2020 16:27

Added missing tests for ListView and virtual mode

dbd0a03

vladimir-krestov force-pushed the Issue-3962_ListView_is_in_virtual_mode_throws_exception branch from 9945bc4 to bc28874 Compare September 29, 2020 13:28

vladimir-krestov self-assigned this Sep 29, 2020

RussKie approved these changes Sep 30, 2020

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RussKie merged commit d304584 into dotnet:release/5.0 Sep 30, 2020

RussKie deleted the Issue-3962_ListView_is_in_virtual_mode_throws_exception branch September 30, 2020 02:20

vladimir-krestov mentioned this pull request Sep 30, 2020

Adding Toggle pattern support for ListView items with checkboxes #4039

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ghost locked as resolved and limited conversation to collaborators Jan 30, 2022

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Fix ListView is in virtual mode #3963

Fix ListView is in virtual mode #3963

SergeySmirnov-Akvelon commented Sep 21, 2020 •

edited

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codecov bot commented Sep 25, 2020 •

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RussKie Sep 28, 2020

RussKie Sep 28, 2020

Fix ListView is in virtual mode #3963

Fix ListView is in virtual mode #3963

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SergeySmirnov-Akvelon commented Sep 21, 2020 • edited Loading

Proposed changes

Customer Impact

Regression?

Risk

Test methodology

Test environment(s)

Accessibility Testing

Microsoft Reviewers: Open in CodeFlow

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codecov bot commented Sep 25, 2020 • edited Loading

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SergeySmirnov-Akvelon commented Sep 21, 2020 •

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