Question

我有以下代码，我可以从我的通用应用程序调用，它工作正常

// create our request with our data
var data = new JsonObject();
data.Add("param", JsonValue.CreateStringValue("abc"));

// convert to bytes
var dataAsBytes = System.Text.Encoding.UTF8.GetBytes(data.Stringify());

var httpRequest = HttpWebRequest.Create(URL + "Add");
httpRequest.Method = "POST";
httpRequest.ContentType = "application/json;charset=utf-8";

using (var requestStream = await httpRequest.GetRequestStreamAsync())
{
    requestStream.Write(dataAsBytes, 0, dataAsBytes.Length);    
}

var httpResponse = await httpRequest.GetResponseAsync();

using (var responseStream = httpResponse.GetResponseStream()) {
    ....
}

但是当我从backgroundTask执行此操作时，此代码似乎停在var httpResponse = await httpRequest.GetResponseAsync()上

要设置我的后台任务，我有以下代码。

var taskRegistered = false;
var taskName = "Upload Background Task";
var background = Windows.ApplicationModel.Background;
var iter = background.BackgroundTaskRegistration.allTasks.first();

while (iter.hasCurrent) {
    var task = iter.current.value;

    if (task.name === taskName) {
        taskRegistered = true;
        break;
    }

    iter.moveNext();
}

if (taskRegistered) {
    successCallback(); // my javascript success callback
} else {
    Windows.ApplicationModel.Background.BackgroundExecutionManager.requestAccessAsync().then(function () {
        var builder = new Windows.ApplicationModel.Background.BackgroundTaskBuilder();

        builder.name = taskName;
        builder.taskEntryPoint = "CordovaApp.Library.UploadTask";
        builder.setTrigger(new Windows.ApplicationModel.Background.TimeTrigger(15, false));
        builder.addCondition(new Windows.ApplicationModel.Background.SystemCondition(Windows.ApplicationModel.Background.SystemConditionType.internetAvailable));

        return builder.register();
    }).done(function () {
        successCallback();
    }, function (err) {
        errorCallback(err);
    });
}

为什么这不起作用？如果我使用visual studio手动运行任务，它会在这一行上进行故障转移，如果我让backgroundTask在15分钟后自行运行，它会在此行上进行故障转移？

Answer 1

问题解决了。

我在我的backgroundTask Run方法中添加了async关键字，因此我可以调用我的异步方法。

而不是这个，我从我的后台Run方法中删除了异步keywork，并使用

调用了异步代码

var result = Task.Run(async() => {
    return myAsyncMethod();
}).Result;

现在全部工作

当backgroundTask使用时，httpRequest.GetResponseAsync（）在windows通用应用程序中失败？

1 个答案: