using System;using System.Collections.Generic;using System.ComponentModel;using System.Linq;using System.Runtime.CompilerServices;using System.Text;using System.Threading.Tasks; namespace COMTRADEConverter{    class ViewModelBase : INotifyPropertyChanged    {        public event PropertyChangedEventHandler PropertyChanged;         protected bool SetProperty<T>(ref T storage, T value, [CallerMemberName] string propertyName = null)        {            if (Object.Equals(storage, value))                return false;             storage = value;            OnPropertyChanged(propertyName);            return true;        }         protected void OnPropertyChanged(string propertyName)        {            PropertyChangedEventHandler handler = PropertyChanged;            if (handler != null)                handler(this, new PropertyChangedEventArgs(propertyName));        }    }}