cannot change my Checkbox.

Question

I am missing something.

I have a property IsChecked.

public partial class NewLecturePageViewModel(IAppService appService, IDataService<User> dataService,
    IAuthenticationService authenticationService) : BaseViewModel {

    [ObservableProperty]
    bool isChecked;

    public ObservableCollection<User> Users { get; set; } = [];

    public ObservableCollection<User> Invited { get; set; } = [];

    [RelayCommand]
    void Appearing() {
        GetUsers();
    }

    private async void GetUsers() {
        Users.Clear();

        var currenUser = await authenticationService.GetLoggedInUser();

        if (currenUser != null) {

            var data = await dataService.GetAllAsync<User>("Users");

            var filterUsers = data
                .Where(u => u.Object.Uid != currenUser?.Uid)
                .Select(u => u.Object)
                .ToList();

            foreach (var filterUser in filterUsers) {

                Users.Add(filterUser);
            }
        }
    }

    [RelayCommand]
    void HandleCheckBox(User user) {

        if (IsChecked is false) {
            appService.DisplayToast("False", ToastDuration.Short, 18);
        } else {
            appService.DisplayToast("true", ToastDuration.Short, 18);

        }

    }
}

and is not checking the box

   <CheckBox
       Grid.RowSpan="3"
       Grid.Column="2"
       IsChecked="{Binding Source={RelativeSource AncestorType={Type vm:NewLecturePageViewModel}}, Path=IsChecked}"
       HorizontalOptions="End"
       VerticalOptions="End">
       <CheckBox.GestureRecognizers>
           <TapGestureRecognizer
               Command="{Binding Source={RelativeSource AncestorType={Type vm:NewLecturePageViewModel}}, Path=HandleCheckBoxCommand}"
               CommandParameter="{Binding .}" />
       </CheckBox.GestureRecognizers>
   </CheckBox>

and I need to be able to check it, in order to send the selected user to the collection.

code

https://github.com/eduardoagr/DemyAI

Answer 1

Hello,

===============Update=============

It appears to work well in Windows, but not Android

Yes, the click event is consumed by DisplayAlert and cannot be transmitted to the checkbox in the Android/iOS platform.

For fix this issue, you can implement this ObservableObject object and change it to partial class, then add [ObservableProperty] to the isInvited property, then this property can be changed at the runtime.

public partial class User:ObservableObject
{
    [ObservableProperty]
    public bool isInvited;
...
}

After that, we can use Conditional compilation to fix this different platform issue. For iOS and Android, we can change this IsInvited value by ourselves, for windows, you can keep this implement.

   [RelayCommand]
    void HandleCheckBox(User user) {


#if ANDROID || IOS


       if (user.IsInvited is false)
        {
            user.IsInvited=true;
            appService.DisplayAlert("Info", "true", "ok");
        }
        else
        {
            user.IsInvited = false;
            appService.DisplayAlert("Info", "false", "ok");

       }
#elif WINDOWS
         if (user.IsInvited is false) {
            appService.DisplayAlert("Info", "False", "ok");
        } else {
            appService.DisplayAlert("Info", "Yes", "ok");

       }
#endif


   }

Best Regards,

Leon Lu

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