'Observable Collection crashes while updating values

Not able to replace entire observable collection. As it throws exception. How do I replace entire observable collection item? The suggested answers from other threads didn't work. Tried the following. Any suggestion would help on this.

Xaml

       <Picker                               
          x:Name=“Picker1”
          Style="{StaticResource PickerStyle}"
          ItemsSource="{Binding CodeNumberList}"
          SelectedItem="{Binding CodeNumberText}”>
                                <Picker.Behaviors>
                                    
                                  <xct:EventToCommandBehavior
                                          EventName="SelectedIndexChanged"
                                          Command="{Binding ItemChangedCommand}"
                                          CommandParameter="{Binding Source={x:Reference Picker1},
                                                                     Path=SelectedItem}"/>

                                </Picker.Behaviors>
       </Picker>

       <Picker                               
          x:Name=“Picker2”
          Style="{StaticResource PickerStyle}"
          ItemsSource="{Binding PhoneNumberList}"
          SelectedItem="{Binding PhoneNumberText}”>
                                    
       </Picker>

ViewModel

    private ObservableCollection<string> _phumberList;
    public ObservableCollection<string> PhNumberList
    {
        get
        {
            return _phumberList;
        }
        set
        {
            _phumberList = value;
            RaisePropertyChanged(nameof(this.PhNumberList));
        }
    }

    private void ItemChangedCommandHandler(string obj)
    {
        PopulatePhoneList();
    }

    private void PopulatePhoneList()
    {
// tried clearing PhNumberList.Clear() and then added items, that didn't work too 

//Invalid cast exception thrown in below line

        PhNumberList = new ObservableCollection<string>();
        foreach (var item in CurrentUser?.InformationDetailItems)
        {
            PhNumberList.Add (item.PhoneNumber);
        }
    }

public On NavigatedTo(){
// populate default pickerList
PopulatePhoneList();
}

Exception : //Invalid cast exception thrown in below line

PhNumberList = new ObservableCollection();

Stack Trace

  at (wrapper castclass) System.Object.__castclass_with_cache(object,intptr,intptr)
  at Prism.Commands.DelegateCommand`1[T].CanExecute (System.Object parameter) [0x00000] in d:\a\1\s\Source\Prism\Commands\DelegateCommand{T}.cs:113 
  at Prism.Commands.DelegateCommandBase.System.Windows.Input.ICommand.CanExecute (System.Object parameter) [0x00000] in d:\a\1\s\Source\Prism\Commands\DelegateCommandBase.cs:67 
  at Xamarin.CommunityToolkit.Behaviors.EventToCommandBehavior.OnTriggerHandled (System.Object sender, System.Object eventArgs) [0x00039] in <823f4019dc404dea9e9331c7114e4863>:0 
  at Xamarin.Forms.Picker.OnSelectedIndexChanged (System.Object bindable, System.Object oldValue, System.Object newValue) [0x00012] in D:\a\1\s\Xamarin.Forms.Core\Picker.cs:283 
  at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.Internals.SetValueFlags attributes, System.Boolean silent) [0x00120] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:512 
  at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.Internals.SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x00173] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:446 
  at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value, System.Boolean fromStyle, System.Boolean checkAccess) [0x0004d] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:374 
  at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:349 
  at Xamarin.Forms.Picker.set_SelectedIndex (System.Int32 value) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Picker.cs:114 
  at Xamarin.Forms.Picker.OnItemsCollectionChanged (System.Object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e) [0x00007] in D:\a\1\s\Xamarin.Forms.Core\Picker.cs:205 
  at (wrapper delegate-invoke) <Module>.invoke_void_object_NotifyCollectionChangedEventArgs(object,System.Collections.Specialized.NotifyCollectionChangedEventArgs)
  at System.Collections.ObjectModel.ObservableCollection`1[T].OnCollectionChanged (System.Collections.Specialized.NotifyCollectionChangedEventArgs e) [0x00018] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/external/corefx/src/System.ObjectModel/src/System/Collections/ObjectModel/ObservableCollection.cs:263 
  at System.Collections.ObjectModel.ObservableCollection`1[T].OnCollectionReset () [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/external/corefx/src/System.ObjectModel/src/System/Collections/ObjectModel/ObservableCollection.cs:362 
  at System.Collections.ObjectModel.ObservableCollection`1[T].ClearItems () [0x00018] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/external/corefx/src/System.ObjectModel/src/System/Collections/ObjectModel/ObservableCollection.cs:166 
  at System.Collections.ObjectModel.Collection`1[T].Clear () [0x00014] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/external/corefx/src/Common/src/CoreLib/System/Collections/ObjectModel/Collection.cs:81 
  at Xamarin.Forms.Internals.LockableObservableListWrapper.InternalClear () [0x00000] in D:\a\1\s\Xamarin.Forms.Core\LockableObservableListWrapper.cs:71 
  at Xamarin.Forms.Picker.ResetItems () [0x00009] in D:\a\1\s\Xamarin.Forms.Core\Picker.cs:273 
  at Xamarin.Forms.Picker.OnItemsSourceChanged (System.Collections.IList oldValue, System.Collections.IList newValue) [0x0004c] in D:\a\1\s\Xamarin.Forms.Core\Picker.cs:231 
  at Xamarin.Forms.Picker.OnItemsSourceChanged (Xamarin.Forms.BindableObject bindable, System.Object oldValue, System.Object newValue) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Picker.cs:213 
  at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.Internals.SetValueFlags attributes, System.Boolean silent) [0x00120] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:512 
  at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.Internals.SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x00173] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:446 
  at Xamarin.Forms.BindingExpression.ApplyCore (System.Object sourceObject, Xamarin.Forms.BindableObject target, Xamarin.Forms.BindableProperty property, System.Boolean fromTarget) [0x00226] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:160 
  at Xamarin.Forms.BindingExpression.Apply (System.Boolean fromTarget) [0x0003e] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:56 
  at Xamarin.Forms.BindingExpression+BindingExpressionPart.<PropertyChanged>b__49_0 () [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:762 
  at Xamarin.Forms.BindingExpression+BindingExpressionPart.PropertyChanged (System.Object sender, System.ComponentModel.PropertyChangedEventArgs args) [0x000cb] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:773 
  at Xamarin.Forms.BindingExpression+WeakPropertyChangedProxy.OnPropertyChanged (System.Object sender, System.ComponentModel.PropertyChangedEventArgs e) [0x00012] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:666 
  at (wrapper delegate-invoke) <Module>.invoke_void_object_PropertyChangedEventArgs(object,System.ComponentModel.PropertyChangedEventArgs)
  at Prism.Mvvm.BindableBase.OnPropertyChanged (System.ComponentModel.PropertyChangedEventArgs args) [0x00000] in d:\a\1\s\Source\Prism\Mvvm\BindableBase.cs:99 
  at Prism.Mvvm.BindableBase.OnPropertyChanged (System.String propertyName) [0x00000] in d:\a\1\s\Source\Prism\Mvvm\BindableBase.cs:90 
  at Prism.Mvvm.BindableBase.RaisePropertyChanged (System.String propertyName) [0x00000] in d:\a\1\s\Source\Prism\Mvvm\BindableBase.cs:76 
-->at ProjectMobile.ViewModels.DarFormPageViewModel.set_EquipmentNumberList (System.Collections.ObjectModel.ObservableCollection`1[T] value) [0x00008] in /Users/vpo1/Project-Mobile/MobileApp/ProjectMobile.ViewModels/PhFormPageViewModel:104 <-- 
  at ProjectMobile.ViewModels.DarFormPageViewModel.PopulateEquipmentList (System.Boolean IsFromNavigatedTo) [0x00013] in /Users/vpo1/Project-Mobile/MobileApp/ProjectMobile.ViewModels/PhFormPageViewModel:940 
  at ProjectMobile.ViewModels.DarFormPageViewModel.DeliveryItemChangedCommandHandler (System.String obj) [0x00008] in /Users/vpo1/Project-Mobile/MobileApp/ProjectMobile.ViewModels/PhFormPageViewModel:61 
  at Prism.Commands.DelegateCommand`1[T].Execute (T parameter) [0x00000] in d:\a\1\s\Source\Prism\Commands\DelegateCommand{T}.cs:82 
  at Prism.Commands.DelegateCommand`1[T].Execute (System.Object parameter) [0x00000] in d:\a\1\s\Source\Prism\Commands\DelegateCommand{T}.cs:103 
  at Prism.Commands.DelegateCommandBase.System.Windows.Input.ICommand.Execute (System.Object parameter) [0x00000] in d:\a\1\s\Source\Prism\Commands\DelegateCommandBase.cs:62 
  at Xamarin.CommunityToolkit.Behaviors.EventToCommandBehavior.OnTriggerHandled (System.Object sender, System.Object eventArgs) [0x00042] in <823f4019dc404dea9e9331c7114e4863>:0 
  at Xamarin.Forms.Picker.OnSelectedIndexChanged (System.Object bindable, System.Object oldValue, System.Object newValue) [0x00012] in D:\a\1\s\Xamarin.Forms.Core\Picker.cs:283 
  at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.Internals.SetValueFlags attributes, System.Boolean silent) [0x00120] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:512 
  at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.Internals.SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x00173] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:446 
  at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value, System.Boolean fromStyle, System.Boolean checkAccess) [0x0004d] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:374 
  at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:349 
  at Xamarin.Forms.Picker.set_SelectedIndex (System.Int32 value) [0x00000] in D:\a\1\s\Xamarin.Forms.Core\Picker.cs:114 
  at Xamarin.Forms.Picker.UpdateSelectedIndex (System.Object selectedItem) [0x00008] in D:\a\1\s\Xamarin.Forms.Core\Picker.cs:296 
  at Xamarin.Forms.Picker.OnSelectedItemChanged (Xamarin.Forms.BindableObject bindable, System.Object oldValue, System.Object newValue) [0x00006] in D:\a\1\s\Xamarin.Forms.Core\Picker.cs:289 
  at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.Internals.SetValueFlags attributes, System.Boolean silent) [0x00120] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:512 
  at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.Internals.SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x00173] in D:\a\1\s\Xamarin.Forms.Core\BindableObject.cs:446 
  at Xamarin.Forms.BindingExpression.ApplyCore (System.Object sourceObject, Xamarin.Forms.BindableObject target, Xamarin.Forms.BindableProperty property, System.Boolean fromTarget) [0x00226] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:160 
  at Xamarin.Forms.BindingExpression.Apply (System.Boolean fromTarget) [0x0003e] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:56 
  at Xamarin.Forms.BindingExpression+BindingExpressionPart.<PropertyChanged>b__49_0 () [0x00000] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:762 
  at Xamarin.Forms.BindingExpression+BindingExpressionPart.PropertyChanged (System.Object sender, System.ComponentModel.PropertyChangedEventArgs args) [0x000cb] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:773 
  at Xamarin.Forms.BindingExpression+WeakPropertyChangedProxy.OnPropertyChanged (System.Object sender, System.ComponentModel.PropertyChangedEventArgs e) [0x00012] in D:\a\1\s\Xamarin.Forms.Core\BindingExpression.cs:666 
  at (wrapper delegate-invoke) <Module>.invoke_void_object_PropertyChangedEventArgs(object,System.ComponentModel.PropertyChangedEventArgs)
  at Prism.Mvvm.BindableBase.OnPropertyChanged (System.ComponentModel.PropertyChangedEventArgs args) [0x00000] in d:\a\1\s\Source\Prism\Mvvm\BindableBase.cs:99 
  at Prism.Mvvm.BindableBase.OnPropertyChanged (System.String propertyName) [0x00000] in d:\a\1\s\Source\Prism\Mvvm\BindableBase.cs:90 
  at Prism.Mvvm.BindableBase.RaisePropertyChanged (System.String propertyName) [0x00000] in d:\a\1\s\Source\Prism\Mvvm\BindableBase.cs:76 
  at ProjectMobile.ViewModels.DarFormPageViewModel.set_BolNumberText (System.String value) [0x00008] in /Users/vpo1/Project-Mobile/MobileApp/ProjectMobile.ViewModels/PhFormPageViewModel:118 
  at ProjectMobile.ViewModels.DarFormPageViewModel.OnNavigatedTo (Prism.Navigation.INavigationParameters parameters) [0x00170] in /Users/vpo1/Project-Mobile/MobileApp/ProjectMobile.ViewModels/PhFormPageViewModel:863

Solution 1:^[1]

Removing this part of the code should resolve the problem:

                          <xct:EventToCommandBehavior
                                  EventName="SelectedIndexChanged"
                                  Command="{Binding ItemChangedCommand}"
                                  CommandParameter="{Binding Source={x:Reference Picker1},
                                                             Path=SelectedItem}"/>

This can be done in many other ways, like using the CodeNumberText property to handle it. As it is likely a bug in that open source component you can submit the bug to their GitHub or fix it yourself.

Sources

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Source: Stack Overflow

Solution	Source
Solution 1	Ivan IÄin

'Observable Collection crashes while updating values

Solution 1:[1]

Sources

Related Questions

Solution 1:^[1]