VisualStateManager Setter Fails for Namespaced Custom Controls in .NET MAUI 10.0.0-preview.7

[PriyadharshniM]

Description

• In .NET MAUI Preview 7, a custom control used in XAML fails to resolve at compile time (XC0000) when VisualStateManager with Setters is defined inside the control usage.

• The same code compiles and runs in Preview 6, so this appears to be a regression in Preview 7’s XAML compiler/type resolution.

Expected behavior

The XAML compiler resolves customControl:MyBorder and compiles successfully.
VisualState setters apply at runtime.

Actual behavior

Build fails with XC0000 complaining it cannot resolve the custom control type.

Error output
XC0000: Cannot resolve type "http://schemas.microsoft.com/dotnet/2021/maui:MyBorder".
File: MainPage.xaml, line 17 (the custom control usage).

Steps to Reproduce

1. Create a new .NET MAUI app.
2. Add a custom control class, e.g., MyBorder in namespace CustomBorder (assembly: TextSample), deriving from Border.
3. Use the control in a XAML page with a clr-namespace mapping: xmlns:customControl="clr-namespace:CustomBorder;assembly=TextSample"
4. Add VisualStateManager.VisualStateGroups with VisualState.Setters targeting a property such as Stroke inside the custom control element.
5. Build the project (any target).

TestSample.zip

Link to public reproduction project repository

No response

Version with bug

10.0.0-preview.7

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

10.0.0-preview.6

Affected platforms

Windows

Affected platform versions

All Platform (Windows, Android, MacOS and iOS)

Did you find any workaround?

Use fully qualified property syntax in the setter:

<Setter Property="controls:MyBorder.Stroke" Value="Red" />

This workaround works in some cases but is inconsistent across platforms and scenarios.

Relevant log output

[similar-issues-ai]

We've found some similar issues:

• XamlC error XC0000 when using VisualState on custom control #31186 , similarity score: 82%

If any of the above are duplicates, please consider closing this issue out and adding additional context in the original issue.

Note: You can give me feedback by 👍 or 👎 this comment.

[nivetha-nagalingam]

The issue has been verified in Visual Studio Code 1.103.1 with MAUI Version 10.0.0-preview.7.25406.3 It can be reproduced on the Android, iOS, Catalyst and Windows Platforms. Also it does not reproduced on 10.0.0-preview 6.

[anandhan-rajagopal]

Duplicate of #31186