ObservableObject.cs (WPF MVVM)

using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.CompilerServices;

public class ObservableObject : INotifyPropertyChanged {
    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string propertyName) {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

    protected virtual bool OnPropertyChanged<T>(ref T backingField, T value, [CallerMemberName] string propertyName = "") {
        if (EqualityComparer<T>.Default.Equals(backingField, value))
            return false;

        backingField = value;
        OnPropertyChanged(propertyName);
        return true;
    }
}