警告 C4451:使用 ref 类 BackgroundTaskDeferral 会导致无效的封送处理 [英] Warning C4451: Usage of ref class BackgroundTaskDeferral can lead to invalid marshaling

问题描述

关于我的通用应用项目，我收到编译警告:

Regarding my universal app project, I am getting compilation warning:

警告 C4451:BackgroundServerTasks::ServerTask::Run::::deferral":在此上下文中使用引用类Windows::ApplicationModel::Background::BackgroundTaskDeferral"会导致对象的无效封送跨上下文

注意:考虑改用Platform::Agile"

在这个文件.我该如何解决此警告?显然，这是由于我在 create_task 中使用了 BackgroundTaskDeferral.除了 这篇文章 解决了这个问题，但我不确定它是否适用于这种情况.

in this file. How could I resolve this warning? Apparently, it is due to my using the BackgroundTaskDeferral within a create_task. I found no solution on Bing except for this post which dismisses the problem but I am not sure if it is applicable in this case.

推荐答案

让我惊讶的是 Windows::ApplicationModel::Background::BackgroundTaskDeferral 并不敏捷.

It surprises me that Windows::ApplicationModel::Background::BackgroundTaskDeferral is not agile.

尝试在相同的上下文中完成延期，即:

Try completing the deferral in the same context, i.e.:

create_task(writer->StoreAsync()).then([this, deferral](unsigned int n)
{
    deferral->Complete();
}, task_continuation_context::use_current());

另一种选择是使用 Platform::Agile<> 包装器:

Another option is to use a Platform::Agile<> wrapper:

Platform::Agile<Windows::ApplicationModel::Background::BackgroundTaskDeferral> Deferral;

// ...

Deferral = taskInstance->GetDeferral();

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