新类对象错误：对象引用未设置为对象的实例 [重复]

问：

我遇到了这个错误： NullReferenceException：对象引用未设置为对象的实例

创建 countStats 对象时，它是 NULL，之后我尝试为此类的字段赋值并得到此错误。 我做错了什么？

public async Task<MainPageViewModel> GetMainPageViewModelAsync()
        {
            var model = new MainPageViewModel();
            var countStats = new StatsCountsViewModel(); // NULL

            if (!_cache.TryGetValue("CountsStats", out countStats))
            {
                var result = await _contextRepository.GetStatsMainPageAsync();

                countStats.CountSms = "300"; //ERROR
                countStats.CountUsers = "600";
                countStats.CountSuccessForecast = "1228";

                model.Stats = countStats;

                _cache.Set("CountsStats", countStats, new MemoryCacheEntryOptions
                {
                    AbsoluteExpirationRelativeToNow = TimeSpan.FromMinutes(10)
                });
            }

            var forecasts = await _contextRepository.GetForecastsOnSaleAsync();

            foreach (var item in forecasts)
            {
                model.Forecasts.Add(item);
                model.Bookmaker.Add(await _contextRepository.GetBookmakersForForecastsAsync(item.Id));
            }

            return model;

        }

 public class StatsCountsViewModel
    {
        public string CountUsers { get; set; }
        public string CountSms { get; set; }
        public string CountSuccessForecast { get; set; }

    }