C# ConcurrentDictionary-添加或更新问题

我正在使用下面的代码尝试根据dictionary对象的键更新该对象中的值

public static ConcurrentDictionary<string, SingleUserStatisticsViewModel> UsersViewModel = new ConcurrentDictionary<string, SingleUserStatisticsViewModel>();

var userSession = new UserSessionStatistic()
{
    Id = "12345", Browser = "Netscape"
};
var userViewModel = new SingleUserStatisticsViewModel()
{
    UserSessionStatistic = userSession,
    StartTime = DateTime.Now
};

MyStaticClass.UsersViewModel.AddOrUpdate(userViewModel.UserSessionStatistic.Id, userViewModel, (key, model) => model);

//尝试更新

MyStaticClass.UsersViewModel.AddOrUpdate(userViewModel.UserSessionStatistic.Id, userViewModel, (key, model) => model);

        var userSession2 = new UserSessionStatistic()
        {
            Id = "12345",
            Browser = "not getting updated????"
        };
        var userViewModel2 = new SingleUserStatisticsViewModel()
        {
            UserSessionStatistic = userSession2,
            StartTime = DateTime.Now
        };

MyStaticClass.UsersViewModel.AddOrUpdate(userViewModel2.UserSessionStatistic.Id, userViewModel2, (key, model) => model);

但是

userViewModel2

中的

UsersessionStatistic

对象在ConcurrentDictionary中没有得到更新（它的浏览器属性仍然是

“Netscape”

），我做错了什么？

关于值工厂，：

MyStaticClass.UsersViewModel.AddOrUpdate(userViewModel.UserSessionStatistic.Id, userViewModel, (key, model) => model);

updateValueFactory类型：System.Func 函数，用于根据 键的现有值

MyStaticClass.UsersViewModel.AddOrUpdate(userViewModel.UserSessionStatistic.Id, userViewModel, (key, model) => model);

这意味着您要将现有值传递给它。您需要将其更新为新的：

MyStaticClass.UsersViewModel.AddOrUpdate(userViewModel.UserSessionStatistic.Id, userViewModel, (key, model) => model);

MyStaticClass.UsersViewModel.AddOrUpdate(userViewModel2.UserSessionStatistic.Id,
                                         userViewModel2, 
                                         (key, oldModel) => userViewModel2);

---

您确定要添加到同一个ConcurrentDictionary吗？（因为MyStaticClass！=信号静态）。看到你的代码，它应该能工作…@Sharped。是的，我是100%舒尔，都一样ConcurrentDictionary@Sharped. 哦，对不起，那只是个打字错误。我把它修好了，那是因为lambda。lambda将旧值作为参数=>（key，oldValue）=>oldValue查看msdn=>