RelayCommand attribute only works in .Net 6 and above?

[tp1415926535]

Describe the bug

WPF, Using the [RelayCommand] in versions lower than .Net6 (.Net 5, .Net core3.1 etc.) will not prompt for the need to set partial for the class, and cause binding error at runtime: System.Windows.Data Error: 40 : BindingExpression path error: 'ButtonClickCommand' property not found on 'object' ''ViewModel' (HashCode=47044325)'. BindingExpression:Path=ButtonClickCommand; DataItem='ViewModel' (HashCode=47044325); target element is 'Button' (Name=''); target property is 'Command' (type 'ICommand')

Regression

No response

Steps to reproduce

• ViewModel

    public partial class ViewModel
    {
        [RelayCommand]
        public void ButtonClick(object param)
        {
            Console.WriteLine(param);
        }
    }

• MainWindow.xaml.cs

        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = new ViewModel();
        }

• MainWindow.xaml

    <Grid>
        <Button Command="{Binding ButtonClickCommand}"/>
    </Grid>

Expected behavior

Support lower Net Version

Screenshots

No response

IDE and version

VS 2019

IDE version

No response

Nuget packages

• [ ] CommunityToolkit.Common
• [ ] CommunityToolkit.Diagnostics
• [ ] CommunityToolkit.HighPerformance
• [X] CommunityToolkit.Mvvm (aka MVVM Toolkit)

Nuget package version(s)

8.2.2

Additional context

No response

Help us help you

Yes, I'd like to be assigned to work on this item