Skip to content

Fix NRE in CarouselViewController UpdateTemplatedCell on iOS when bindingContext is null #10

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
Copilot wants to merge 3 commits into
base: main
Choose a base branch
from
Draft

Fix NRE in CarouselViewController UpdateTemplatedCell on iOS when bindingContext is null #10

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
1534992
Initial plan
Copilot Jul 10, 2025
7a56962
Fix NRE in CarouselViewController UpdateTemplatedCell on iOS
Copilot Jul 10, 2025
1a0f8ef
Use early return approach for null bindingContext in UpdateTemplatedC…
Copilot Jul 10, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
21 changes: 19 additions & 2 deletions src/Controls/src/Core/Handlers/Items/iOS/ItemsViewController.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -458,6 +458,13 @@ protected virtual void UpdateTemplatedCell(TemplatedCell cell, NSIndexPath index

var bindingContext = ItemsSource[indexPath];

// If bindingContext is null (can happen during collection updates),
// we can't meaningfully update the cell, so return early to avoid issues
if (bindingContext is null)
{
return;
}

// If we've already created a cell for this index path (for measurement), re-use the content
if (_measurementCells != null && _measurementCells.TryGetValue(bindingContext, out TemplatedCell measurementCell))
{
Expand All @@ -467,7 +474,7 @@ protected virtual void UpdateTemplatedCell(TemplatedCell cell, NSIndexPath index
}
else
{
cell.Bind(ItemsView.ItemTemplate, ItemsSource[indexPath], ItemsView);
cell.Bind(ItemsView.ItemTemplate, bindingContext, ItemsView);
}

cell.LayoutAttributesChanged += CellLayoutAttributesChanged;
Expand Down Expand Up @@ -856,13 +863,23 @@ public UICollectionViewCell CreateMeasurementCell(NSIndexPath indexPath)
return cell;
}

// Check if bindingContext is null before creating measurement cell
var bindingContext = ItemsSource[indexPath];
if (bindingContext is null)
{
// Return a basic templated cell without binding if bindingContext is null
return CreateAppropriateCellForLayout();
}

TemplatedCell templatedCell = CreateAppropriateCellForLayout();

UpdateTemplatedCell(templatedCell, indexPath);

// Keep this cell around, we can transfer the contents to the actual cell when the UICollectionView creates it
if (_measurementCells != null)
_measurementCells[ItemsSource[indexPath]] = templatedCell;
{
_measurementCells[bindingContext] = templatedCell;
}

return templatedCell;
}
Expand Down