Remove top item of ObservableCollection

Question

I have a Maui.net MVVM app that pings a website every xx seconds and display the ping results in a listview (for demonstrations sake I removed the ping class and instead increment a counter).

After 5 pings I want the top ping result removed so that only the last 5 ping results show in the listview.

My question is: How can I remove the top item in the ObservableCollection .

oc.Remove(), oc.RemoveAt(0) and many other variations. I Usually get the following error:

"System.ArgumentOutOfRangeException: 'This collection cannot work with indices larger than Int32.MaxValue - 1 (0x7FFFFFFF - 1). (Parameter 'index')'"

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="xPing_Maui.Views.MainPage"
             BackgroundColor="LightGray" >
    <ContentPage.MenuBarItems>
        <MenuBarItem Text="File">
            <MenuFlyoutItem Text="Save"/>
            <MenuFlyoutItem  Text="Exit"/>
        </MenuBarItem>
        <MenuBarItem Text="Settings">
            <MenuFlyoutItem Text="Email Settings"/>
            <MenuFlyoutItem  Text="Ping Settings"/>
        </MenuBarItem>
    </ContentPage.MenuBarItems>
    <VerticalStackLayout>
        <ListView ItemsSource="{Binding ListV}" SelectionMode="Single"  Background="Gray"  SeparatorVisibility="None" Margin="20,20,20,20">
                       
        </ListView>
        <Grid>
            
        </Grid>
    </VerticalStackLayout>
</ContentPage>

Main Page code behind

using System.Diagnostics;
using xPing_Maui.ViewModels;

namespace xPing_Maui.Views;

public partial class MainPage : ContentPage
{
    
    public MainPage()
	{
		InitializeComponent();
         
        BindingContext = new VMMainPage();
    }
}

ViewModel

using Microsoft.VisualBasic.FileIO;
using PropertyChanged;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using xPing_Maui.Helper;
using xPing_Maui.Models;

namespace xPing_Maui.ViewModels
{
   

  //  [AddINotifyPropertyChangedInterface]
    public class LVMainPage
    {
        public ObservableCollection<string> ListV { get; set; }
        
        PingClass pg = new PingClass ();


        [Obsolete]
        public LVMainPage()
        {
            ListV = new ObservableCollection<string>();
            int Counter = 0;
            int cnt = 0;         
            
            Device.StartTimer(new TimeSpan(0, 0, 4), () =>
            {              
                ListV.Add(Counter.ToString());
                Counter++;   
              
                cnt++;
                if(cnt == 5)
                {
                    // Delete first row in the ObservableCollection
                    ListV.RemoveAt(0);
                    cnt = 0;                    
                }
               return true; 
            });
        }
    }
}

Answer 1

It seems to be a problem of MAUI. To work around, try removing the item before adding the new one, for example:

Device.StartTimer( new TimeSpan( 0, 0, 4 ), ( ) =>
{
    if( ListV.Count >= 5)
    {
        ListV.RemoveAt( 0 );
    }

    ListV.Add( Counter.ToString( ) );
    Counter++;

    return true;
} );

By the way, some of the classes and functions are obsolete.