AOT throws exception when using the custom control

[sudharsan-narayanan]

Describe the bug

Hi Team,

I have prepared the sample with the custom control by using the AOT support. In Custom sample, I have used the ComboBox ItemsSource and assigned the Observerable String to ItemsSource. So, When AOT is enable, it throws exception when it is empty or assigned any items to ItemsSource.

Please find the image below,

Attached the sample and exception below,

CustomSampleAOT.zip

Steps to reproduce the bug

1. Open the Sample.
2. Ensure the AOT is enabled in the project.
3. Now, run the sample.
4. Note: Exception is thrown in AOT sample.

Expected behavior

Sample should run smoothly without any issue.

Screenshots

No response

NuGet package version

WinUI 3 - Windows App SDK 1.6.5: 1.6.250205002

Windows version

No response

Additional context

No response

[manodasanW]

If you put the property <AllowUnsafeBlocks>true</AllowUnsafeBlocks> in your CustomControlAOT library project, that should resolve your issue.

Scenarios using generics require our source generator to generate sources that makes use of unsafe, but if unsafe isn't enabled, we instead emit a diagnostic which you should see if you hover over the this on the above selected line. Some of these diagnostics are emitted as warnings if IsAotCompatible is set to true. But in the case of collections which only use built-in types, you would also need to set <CsWinRTAotWarningLevel>2</CsWinRTAotWarningLevel> to promote that from a diagnostic to a warning.

[sudharsan-narayanan]

If you put the property <AllowUnsafeBlocks>true</AllowUnsafeBlocks> in your CustomControlAOT library project, that should resolve your issue.

Scenarios using generics require our source generator to generate sources that makes use of unsafe, but if unsafe isn't enabled, we instead emit a diagnostic which you should see if you hover over the this on the above selected line. Some of these diagnostics are emitted as warnings if IsAotCompatible is set to true. But in the case of collections which only use built-in types, you would also need to set <CsWinRTAotWarningLevel>2</CsWinRTAotWarningLevel> to promote that from a diagnostic to a warning.

After adding the above tag in CustomControlAOT. Facing the below exception

Please let us know, how to resolve this?

This exception occurs when the items are added in itemsCollectionChanged event to Base class of ListView. This exception is thrown, if the AOT is enabled. Please find the code below,

` private void OnItemsCollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
{
if (this.ItemsSource != null)
{
return;
}

        if (e.Action == NotifyCollectionChangedAction.Add)
        {
            if (e.NewItems != null && e.NewItems.Count > 0)
            {
                if (base.Items.Count > e.NewStartingIndex)
                {
                    base.Items.Insert(e.NewStartingIndex, e.NewItems[0]);
                }
                else
                {
                    base.Items.Add(e.NewItems[0] ?? null);
                }
            }
        }
        else if (e.Action == NotifyCollectionChangedAction.Remove)
        {
            if (e.OldStartingIndex != -1)
            {
                base.Items.RemoveAt(e.OldStartingIndex);
            }
            else if (e.OldItems != null && e.OldItems.Count > 0)
            {
                base.Items.Remove(e.OldItems[0]);
            }
        }
        else if (e.Action == NotifyCollectionChangedAction.Reset && base.Items.Any())
        {
            base.Items.Clear();
        }
    }

`

Base Class --> ListView

[sudharsan-narayanan]

Any update on this?

[snigdha011997]

Hi @sudharsan-narayanan, facing the below error with the steps provided do let us know if anything missed:

[cdock1029]

Not stale, I use Syncfusion Grid with WinUI and would like to see AOT compatibility. @sudharsan-narayanan any progress?

[microsoft-github-policy-service]

This issue has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 7 days. It will be closed if no further activity occurs within 7 days of this comment.