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

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