MAUIG2045 false warning when binding to CommunityToolkit.Mvvm [RelayCommand] generated commands #34086
Description
When using CommunityToolkit.Mvvm with [RelayCommand], MAUI’s XAML compiler (XamlC) cannot see the generated command property during compile time. This results in a false MAUIG2045 warning:
Binding: Property "ColorChangedCommand" not found on "MainPageViewModel".
The binding will use slower reflection-based binding at runtime.
If this property is generated by another source generator, consider reporting this..
Binding: Property "ColorChangedCommand" not found on "MainPageViewModel". The binding will use slower reflection-based binding at runtime. If this property is generated by another source generator, consider reporting this...
However, the property does exist at runtime:
[RelayCommand]
public void OnColorChanged(Color newColor) { ... }
// Generates: public IRelayCommand ColorChangedCommand { get; }
But MAUI compiled bindings cannot see the generated property, causing the warning.
Expected behavior:
MAUI’s XAML compiler should recognize properties generated by other source generators (especially CommunityToolkit.Mvvm, which is widely used).
Actual behavior:
MAUI emits MAUIG2045 even though the property exists and works at runtime.
Repro steps:
- Create a ViewModel using CommunityToolkit.Mvvm
- Add a [RelayCommand] method:
[RelayCommand]
public void OnColorChanged(Color c) { } - Bind to the generated command in XAML:
ColorChangedCommand="{x:Binding ColorChangedCommand}" - Add x:DataType="YourViewModel" to enable compiled bindings
- Build → MAUIG2045 warning appears
Environment: - .NET MAUI 10
- CommunityToolkit.Mvvm 8+
- Windows / Android / iOS
- Visual Studio 2022
Notes:
This appears to be a source generator ordering / visibility issue.
MAUI XamlC runs before the Toolkit generator, so it cannot see the generated members.