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基本上，发生的事情是当尝试更改托管类 (UWP) 的变量时，它会崩溃。此外，如果我尝试修改使用 app 命名空间创建的变量，它似乎只会崩溃。换句话说，如果我创建一个新的 namspace 和托管类，我可以很好地修改变量。

碰撞

void ASynTaskCategories(void)
    {
        concurrency::task_completion_event<Platform::String^> taskDone;
        MainPage^ rootPage = this;
        UberSnip::HELPER::ASYNC_RESPONSE^ responseItem = ref new UberSnip::HELPER::ASYNC_RESPONSE();
        create_task([taskDone, responseItem, rootPage]() -> Platform::String^
        {

            //UBERSNIP API 0.4
            UberSnip::UBERSNIP_CLIENT* UberSnipAPI = new UberSnip::UBERSNIP_CLIENT();

            UberSnipAPI->Http->RequestURL = "http://api.ubersnip.com/categories.php";
            UberSnipAPI->Http->request();
            taskDone.set(UberSnipAPI->Client->BodyResponse);
            responseItem->Body = UberSnipAPI->Client->BodyResponse;
            return "(done)";

        }).then([taskDone, responseItem, rootPage](Platform::String^ BodyResponse) {
            Platform::String^ BR = responseItem->Body;


            cJSON* cats = cJSON_Parse(_string(BR));
            cats = cats->child;
            int *cat_count = new int(cJSON_GetArraySize(cats));
            rootPage->Categories->Clear();

            GENERIC_ITEM^ all_item = ref new GENERIC_ITEM();
            all_item->Title = "All";

            rootPage->Categories->Append(all_item);
            for (int i = 0; i < *cat_count; i++) {
                cJSON* cat = new cJSON();
                cat = cJSON_GetArrayItem(cats, i);

                string *track_title = new string(cJSON_GetObjectItem(cat, "name")->valuestring);

                GENERIC_ITEM gitem;
                gitem.Title = "Hi";

                GENERIC_ITEM^ ubersnipCategory = ref new GENERIC_ITEM();
                ubersnipCategory->Title = _String(*track_title);

                rootPage->Categories->Append(ubersnipCategory);
            }
        });

这不会崩溃

UberSnipAPI->Http->RequestURL = "http://api.ubersnip.com/categories.php";

但是这个确实

all_item->Title = "All";

我几乎肯定它与它在应用程序默认命名空间中以及它在主线程之外被访问有关......至少看起来是这样，因为这实际上是除了实际类之外的唯一区别。

这就是 GENERIC_ITEM 的样子。

[Windows::UI::Xaml::Data::Bindable]
public ref class GENERIC_ITEM sealed {
private:
    Platform::String^ _title = "";
    Platform::String^ _description;
    Windows::UI::Xaml::Media::ImageSource^ _Image;

    event PropertyChangedEventHandler^ _PropertyChanged;

    void OnPropertyChanged(Platform::String^ propertyName)
    {
        PropertyChangedEventArgs^ pcea = ref new  PropertyChangedEventArgs(propertyName);
        _PropertyChanged(this, pcea);
    }
public:
    GENERIC_ITEM() {

    };

    property Platform::String^ Title {
        Platform::String^ get() {
            return this->_title;
        }

        void set(Platform::String^ val) {
            this->_title = val;
            OnPropertyChanged("Title");
        }
    }

    property Platform::String^ Description {
        Platform::String^ get() {
            return this->_description;
        }

        void set(Platform::String^ val) {
            this->_description = val;
            OnPropertyChanged("Description");
        }
    }

    void SetImage(Platform::String^ path)
    {
        Windows::Foundation::Uri^ uri = ref new Windows::Foundation::Uri(path);
        _Image = ref new Windows::UI::Xaml::Media::Imaging::BitmapImage(uri);
    }

};

我知道这个类没有问题，因为如果我在初始线程上运行完全相同的代码，它工作得非常好。

有什么建议么？谢谢！:D

4

1 回答 1

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几个小时后想通了！如果其他人遇到此问题，您所要做的就是使用 Dispatcher 在 UI 上运行在 UI 线程之外不可用的代码。

void loadCats(UberSnip::HELPER::ASYNC_RESPONSE^ responseItem, MainPage^ rootPage) {
    Platform::String^ BR = responseItem->Body;


    cJSON* cats = cJSON_Parse(_string(BR));
    cats = cats->child;
    int *cat_count = new int(cJSON_GetArraySize(cats));
    rootPage->Categories->Clear();

    GENERIC_ITEM^ all_item = ref new GENERIC_ITEM();
    all_item->Title = "All";

    rootPage->Categories->Append(all_item);
    for (int i = 0; i < *cat_count; i++) {
        cJSON* cat = new cJSON();
        cat = cJSON_GetArrayItem(cats, i);

        string *track_title = new string(cJSON_GetObjectItem(cat, "name")->valuestring);

        GENERIC_ITEM gitem;
        gitem.Title = "Hi";

        GENERIC_ITEM^ ubersnipCategory = ref new GENERIC_ITEM();
        ubersnipCategory->Title = _String(*track_title);

        rootPage->Categories->Append(ubersnipCategory);
    }
}

void ASyncTaskCategories(void)
{
    concurrency::task_completion_event<Platform::String^> taskDone;
    MainPage^ rootPage = this;
    UberSnip::HELPER::ASYNC_RESPONSE^ responseItem = ref new UberSnip::HELPER::ASYNC_RESPONSE();

    auto dispatch = CoreWindow::GetForCurrentThread()->Dispatcher;
    auto op2 = create_async([taskDone, responseItem, rootPage, dispatch] {
        return create_task([taskDone, responseItem, rootPage, dispatch]() -> Platform::String^
        {

            //UBERSNIP API 0.4
            UberSnip::UBERSNIP_CLIENT* UberSnipAPI = new UberSnip::UBERSNIP_CLIENT();

            UberSnipAPI->Http->RequestURL = "http://api.ubersnip.com/categories.php";

            try{
                UberSnipAPI->Http->request();
            }
            catch (...) {
                printf("Error");
            }

            int err = UberSnip::UTILS::STRING::StringToAscIIChars(UberSnipAPI->Client->BodyResponse).find("__api_err");

            if (err < 0) {
                if (UberSnip::UTILS::STRING::StringToAscIIChars(UberSnipAPI->Client->BodyResponse).length() < 3) {
                    return;
                }
            }
            taskDone.set(UberSnipAPI->Client->BodyResponse);
            responseItem->Body = UberSnipAPI->Client->BodyResponse;
            dispatch->RunAsync(Windows::UI::Core::CoreDispatcherPriority::High, ref new Windows::UI::Core::DispatchedHandler([=]()
            {
                rootPage->loadCats(responseItem, rootPage);
            }));

            for (int i = 0; i < 100;) {

            }


            return "(done)";

        }).then([taskDone, responseItem, rootPage](Platform::String^ BodyResponse) {
        });

    });

        //rootPage->loadCats(responseItem, rootPage);
}
于 2016-04-14T12:58:38.543 回答