非通用 TaskCompletionSource 或替代 [英] Non-Generic TaskCompletionSource or alternative

问题描述

我正在使用通常异步显示的警报窗口 (Telerik WPF)(代码在打开时继续运行)，我想通过使用 async/await 使其同步.

I'm working with an alert window (Telerik WPF) that is normally displayed asynchronously ( code continues running while it is open) and I want to make it synchronous by using async/await.

我有这个与 TaskCompletionSource 一起工作，但那个类是通用的，当我想要的只是一个普通的 Task 时，它返回一个像 Task 这样的对象代码>，没有返回值.

I have this working with TaskCompletionSource but that class is generic and returns an object like Task<bool> when all I want is a plain Task with no return value.

public Task<bool> ShowAlert(object message, string windowTitle)
{
    var dialogParameters = new DialogParameters { Content = message };

    var tcs = new TaskCompletionSource<bool>();
    dialogParameters.Closed += (s, e) => tcs.TrySetResult(true);

    RadWindow.Alert(dialogParameters);

    return tcs.Task;
}

调用该方法的代码是

await MessageBoxService.ShowAlert("The alert text.")

如何返回一个功能类似的非通用任务，我可以等待直到 dialogParameters.Closed 事件触发?我知道我可以忽略此代码中返回的 bool.我正在寻找与此不同的解决方案.

How can I return a non-generic Task that functions similarly which I can await until the dialogParameters.Closed event fires? I understand that I could just ignore the bool that is being returned in this code. I am looking for a different solution than that.

推荐答案

可以改成:

public Task ShowAlert(object message, string windowTitle)

Task 继承自 Task 所以你可以返回 Task 而只暴露 Task给来电者

Task<bool> inherits from Task so you can return Task<bool> while only exposing Task to the caller

我找到了一个 Microsoft 文档，http://www.microsoft.com/en-us/download/details.aspx?id=19957，Stephen Toub 撰写的题为基于任务的异步模式"的文章，其中的以下摘录推荐了相同的模式.

I found a Microsoft document, http://www.microsoft.com/en-us/download/details.aspx?id=19957, by Stephen Toub titled 'The Task-based Asynchronous pattern' and it has the following excerpt that recommends this same pattern.

没有与 TaskCompletionSource 的非通用对应物.然而，Task 派生自 Task，因此通用 TaskCompletionSource 可用于 I/O 绑定方法，这些方法通过利用带有虚拟 TResult 的源来简单地返回 Task(布尔值是一个很好的默认选择，并且如果开发人员担心 Task 的使用者将其向下转换为 Task，则可以使用私有 TResult 类型)

There is no non-generic counterpart to TaskCompletionSource<TResult>. However, Task<TResult> derives from Task, and thus the generic TaskCompletionSource<TResult> can be used for I/O-bound methods that simply return a Task by utilizing a source with a dummy TResult (Boolean is a good default choice, and if a developer is concerned about a consumer of the Task downcasting it to a Task<TResult>, a private TResult type may be used)

这篇关于非通用 TaskCompletionSource 或替代的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！