public void Start()
{
ItemManager manager = new ItemManager();
WrongInput += new PrintMessage(WrongInputErrorMessage);
while (true)
{
Console.Clear();
UserMenus.MainMenu();
var input = Console.ReadKey(true).Key;
switch (input)
{
case ConsoleKey.D1:
FilterMethod(manager);
break;
case ConsoleKey.D2:
manager.AddNewProduct(this);
break;
case ConsoleKey.D3:
Environment.Exit(0);
break;
default: OnWrongInput("Not a valid input.");
break;
}
}
}