Cannot resolve type only in Release build config

[maslewandowski]

Description

Hi,

When building an iOS release configuration, XAML compilation fails with the following errors:

XamlC error XC0000: Cannot resolve type "http://schemas.microsoft.com/dotnet/2022/maui/toolkit:MediaElement".
XamlC error XC0000: Cannot resolve type "http://schemas.devexpress.com/maui:ChartView".

These errors occur even though the corresponding NuGet packages are referenced:

• CommunityToolkit.Maui.MediaElement
• DevExpress.Maui.Charts
• DevExpress.Maui.Core

The issue does not occur in Debug builds — only in Release (with AOT and trimming).

What i tried:

• <PublishTrimmed>false> in csproj
• <TrimMode>copyused>, <IsTrimmable>false>, <EnableTrimAnalyzer>false>
• Adding <TrimmerRootAssembly> entries for all related libraries
• Ensuring XML namespaces and XAML usage are correct
• Rebuilding clean Debug/Release, validating assemblies are present
• called fakemethods in the code behind files of the styles.xaml to actually use the types that i need. (like here)

Steps to Reproduce

1. Create a new .NET MAUI project targeting iOS.
2. Create a new .NET MAUI Class Library Project targeting iOS.
3. Set Reference from class library to executed project (app)
4. Add CommunityToolkit.Maui.MediaElement and/or DevExpress.Maui.Charts to class library
5. change reference in main project to class library for styles
6. Use a control like <toolkit:MediaElement /> or <dx:ChartView /> in a .xaml file.
7. Build the project in Release mode for net9.0-ios.
8. Observe the XamlC error XC0000 messages.

alternatively just build styles.xaml in sample repo in release build config.

Please help me i want to distribute my app asap.

If you tell me that encapsulation of resources like styles does not work, then tell me please.

Link to public reproduction project repository

https://github.com/maslewandowski/problemwithtrimmingmauiresources

Version with bug

9.0.70 SR7

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

IOS 18.4

Did you find any workaround?

No response

Relevant log output

source\repos\problemwithtrimmingmauiresources\styles\CommunityToolkitStyles.xaml(8,12): XamlC error XC0000: Cannot resolve type "http://schemas.microsoft.com/dotnet/2022/maui/toolkit:MediaElement".
1>Done building project "styles.csproj" -- FAILED.

[jsuarezruiz]

Can you try to add assembly preservation in your main app's MauiProgram.cs?, like:

// Force assembly loading
_ = typeof(CommunityToolkit.Maui.Views.MediaElement);
_ = typeof(DevExpress.Maui.Charts.ChartView);

Or, create a LinkerConfig.xml file.

<assembly fullname="CommunityToolkit.Maui.MediaElement" preserve="all" />
<assembly fullname="DevExpress.Maui.Charts" preserve="all" />
<assembly fullname="DevExpress.Maui.Core" preserve="all" />

[dotnet-policy-service]

Hi @@maslewandowski. We have added the "s/needs-info" label to this issue, which indicates that we have an open question for you before we can take further action. This issue will be closed automatically in 7 days if we do not hear back from you by then - please feel free to re-open it if you come back to this issue after that time.

[dotnet-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 4 days. It will be closed if no further activity occurs within 3 days of this comment. If it is closed, feel free to comment when you are able to provide the additional information and we will re-investigate.