Delete a group from a collectionview from observableCollection

Question

I have a Observablecollection made up of some certain elements (groups). Each element inside it has another ObservableCollection with other elements. I need this to create a CollectionView with groups. If I try to delete a group from my collection, I keep seeing it in the collectionview. Do I need to update the collectionView in some way? If I try to delete a single element within the group, I see the changes, while if I delete the group, in reality the group continues to exist

Group group = MyCollection.Where(x => x.Name == "NameGroup".First(); 
MyCollection.Remove(group);

Answer 1

Hello,​

Welcome to our Microsoft Q&A platform!

Hi, StefanoM-9408. How did you set data binding with the grouped collectionView? I created a basic demo to test the function, it works fine. Here is the related code, you could refer to it.

Check the code:

   //page.xaml  
   <StackLayout Margin="20">  
       <Button Clicked="Button_Clicked"/>  
       <CollectionView ItemsSource="{Binding DataCollection}"  
                           IsGrouped="true">  
           ...  
       </CollectionView>  
   </StackLayout>  
   //page.xaml.cs  
   public partial class Page1 : ContentPage  
   {  
       TestViewModel viewModel;  
       public Page1()  
       {  
           InitializeComponent();  
           viewModel = new TestViewModel();  
           BindingContext = viewModel;  
       }  
     
       private void Button_Clicked(object sender, EventArgs e)  
       {  
           var itemCollection = viewModel.DataCollection.Where(x => x.Name == "group_1").First();  
           if (itemCollection != null)  
           {  
               viewModel.DataCollection.Remove(itemCollection);  
           }  
       }  
   }  

The related Model class and ViewModel class:

   public class TestModel : INotifyPropertyChanged  
   {  
       private string content;  
       public string Content  
       {  
           get  
           {  
               return content;  
           }  
           set  
           {  
               if (content != value)  
               {  
                   content = value;  
                   NotifyPropertyChanged();  
               }  
           }  
       }  
     
       protected virtual void NotifyPropertyChanged([CallerMemberName] string propertyName = "")  
       {  
           PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));  
       }  
     
       public event PropertyChangedEventHandler PropertyChanged;  
   }  
     
   public class TestModelGroup : ObservableCollection<TestModel>, INotifyPropertyChanged  
   {  
       public TestModelGroup(string name, List<TestModel> testModel) : base(testModel)  
       {  
           Name = name;  
       }  
     
       public override string ToString()  
       {  
           return Name;  
       }  
     
       private string name;  
       public string Name  
       {  
           get  
           {  
               return name;  
           }  
           set  
           {  
               if (name != value)  
               {  
                   name = value;  
                   NotifyPropertyChanged();  
               }  
           }  
       }  
     
       protected virtual void NotifyPropertyChanged([CallerMemberName] string propertyName = "")  
       {  
           PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));  
       }  
       public event PropertyChangedEventHandler PropertyChanged;  
   }  
     
   public class TestViewModel  
   {  
       public ObservableCollection<TestModelGroup> DataCollection { get; set; }  
     
       public TestViewModel(bool emptyGroups = false)  
       {  
           DataCollection = new ObservableCollection<TestModelGroup>();  
           CreateDataCollection();  
       }  
     
       private void CreateDataCollection()  
       {  
           //add the data  
       }  
   }  

Best Regards,

Jarvan Zhang

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