По какой причине не обновляется ListView (юзаю WPF MVVM, EF Core, SQL Server)?

Question

[Георгий Кузнецов]

Допустим есть три файла, MainWindowViewModel, TCommand и window.xaml, сама среда разработки видит всё вплоть до типов переменных у полей объекта User (id - string, name - string, age - string, balance - int), но при нажатии на кнопку ShowAll ничего не происходит :

--- ViewModel.cs---

        public event PropertyChangedEventHandler? PropertyChanged;

        public virtual void CheckChanges([CallerMemberName] string property = "")
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(property));
        }


        public List<User> userlist;

        public List<User> UserList
        {
            get { return userlist; }
            set
            {
                userlist = value;
                CheckChanges();
            }
        }

        public TCommand ShowAllDb_Click
        {
            get
            {
                return new TCommand
                (
                    (obj) =>
                    {
                        UserList = new List<User> { new User { ID = "1", Name = "Joe", Age = "25", Balance = 50 } };
                    }
                );
            }
        }

--TCommand--

using System;
using System.Windows.Input;

namespace WPF_SQLOperator
{
    class TCommand : ICommand
    {
        private Action<object> execute;
        private Func<object, bool> canExecute;

        public event EventHandler CanExecuteChanged
        {
            add { CommandManager.RequerySuggested += value; }
            remove { CommandManager.RequerySuggested -= value; }
        }

        public TCommand(Action<object> _execute, Func<object, bool> _canExecute = null)
        {
            execute = _execute;
            canExecute = _canExecute;
        }

        public bool CanExecute(object parameter)
        {
            return canExecute == null || canExecute(parameter);
        }

        public void Execute(object parameter)
        {
            execute(parameter);
        }
    }
}

--window.xaml

<Window x:Class="WPF_SQLOperator.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WPF_SQLOperator"
        mc:Ignorable="d"
        WindowStartupLocation="CenterScreen"
        Title="SQL Operator" Height="735" Width="745" ResizeMode="NoResize">
    <Window.DataContext>
        <local:MainWindowViewModel/>
    </Window.DataContext>
    <Grid>
        <Button Command="{Binding ShowAllDb_Click}" Margin="15,247,0,0" HorizontalAlignment="Left" VerticalAlignment="Top" Height="40" Width="333">
            <TextBlock TextAlignment="Center"><Run Text="*Show all"/></TextBlock>
        </Button>
        <ListView ItemsSource="{Binding UserList}" Margin="200,292,0,0" HorizontalAlignment="Left" VerticalAlignment="Top" Height="396" Width="349">
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="ID" Width="48" DisplayMemberBinding="{Binding ID}" />
                    <GridViewColumn Header="Name" Width="100" DisplayMemberBinding="{Binding Name}" />
                    <GridViewColumn Header="Age" Width="100" DisplayMemberBinding="{Binding Age}" />
                    <GridViewColumn Header="Balance" Width="100" DisplayMemberBinding="{Binding Balance}" />
                </GridView>
            </ListView.View>
        </ListView>
    </Grid>
</Window>

Answer 1

[Георгий Кузнецов]

Уже в который раз на те же грабли: я во ViewModel забыл реализовать интерфейс INotifyPropertyChanged
Т.е сигнатура класса начала выглядела так:

class MainWindowViewModel
{

}

после коррекции так:

class MainWindowViewModel : INotifyPropertyChanged
{

}