EF 5：如何取消longrunning查询的异步任务 [英] EF 5: How to cancel a longrunning query in a async Task

问题描述

在我的应用程序有多个选项卡，从与实体框架5。

In my application I have multiple tabs, displaying data from a database with Entity Framework 5.

当我在标签之间切换，我开始自动加载通过任务中的数据，因为我不想让图形用户界面变得无法响应（此任务需要大约5-10秒）：

When I switch between the tabs I start auto loading the data via a Task, because I don't want the GUI to become unresponsive (this task takes about 5-10 seconds):

public async void LoadData()
{
    [...]

    await Task.Run(
        () =>
            {
                Measurements = DataContext.Measurements
                                  .Where(m => m.MeasureDate = DateTime.Today)
                                  .ToList();
            });

    [...]
}

不过，虽然任务运行的用户仍然可以切换到另一个选项卡，如果他不说，我想取消EF查询和/或任务。

But while the task runs the user still can change to another tab, and if he does that I would like to cancel the EF query and/or the Task.

什么是实现这一目标的最佳方式是什么？

What would be the best way to accomplish this?

推荐答案

在EF5，有没有办法取消查询，因为它不接受的CancellationToken 。你可以阅读更多关于此这里：<一href="http://social.msdn.microsoft.com/Forums/en-US/ad3db060-190a-43a5-bff7-db6fc818a036/entity-framework-cancel-long-running-query"相对=nofollow>实体框架取消长时间运行的查询

In EF5, there is no way to cancel the queries since it doesn't accept CancellationToken. You can read more about this here: entity framework cancel long running query

不过，EF6不支持它。它拥有的所有方法异步版本。因此，了ToList（）也可以是符合 ToListAsync（）对于长时间运行的查询，它确实有支持的CancellationToken 。

However, EF6 does support it. It has async version of all methods. So ToList() could instead be ToListAsync() for long running queries and it does have support for CancellationToken.

PS ：EF 6仍处于测试阶段，截至目前

P.S: EF 6 is still in beta as of now.

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