从Toast Notification打开文件

Question

在我的UWP应用程序中，我下载了一个文件，并使用FolderPicker将其存储在用户选择的位置。下载完成后，我会显示一个ToastNotification。我使用这两个名称空间，如文档中所示。

using Microsoft.QueryStringDotNET; // for receciving arguments
using Microsoft.Toolkit.Uwp.Notifications;

我发送的toast有两个按钮，1)打开文件2)解除。当用户点击第一个按钮时，我想打开下载的文件。

但据我所知，toast只能向应用程序发送字符串参数(如果错误，请纠正我)。为了打开一个文件，需要StorageFile对象( StorageFile的路径是不行的)。

那么，有没有办法从toast中实际打开下载的文件(使用前台或后台激活)？

下载文件的代码：

private async void DownloadButton_Click(object sender, RoutedEventArgs e)
{   
    StorageFolder selectedFolder;   
    try
    {
        selectedFolder = await ChooseFolderAsync();
    }
    catch
    {
        Toast.ShowToast("Something went wrong", ToastRow);
        return;
    }

    Uri downloadLink = new Uri("ValidUri");    

    StorageFile destinationFile = await selectedFolder.CreateFileAsync(selectedAsset.name, CreationCollisionOption.GenerateUniqueName);

    BackgroundDownloader downloader = new BackgroundDownloader();
    downloader.SuccessToastNotification = handler.MakeToastWithButtons("Downloaded", selectedAsset.name, "Open", "Dismiss");
   // downloader.SuccessToastNotification = handler.MakeToast("Downloaded", nameOfFile, string.Empty, 2);
    DownloadOperation download = downloader.CreateDownload(downloadLink, destinationFile);
    download.Priority = BackgroundTransferPriority.High;
    download.CostPolicy = BackgroundTransferCostPolicy.Always;    

    var toast = handler.MakeToast("Downloading...", selectedAsset.name, selectedAsset.contentSize, 12);
    toast.Group = "downloadStartedTag";
    ToastNotificationManager.CreateToastNotifier().Show(toast);

    Progress<DownloadOperation> progressCallback = new Progress<DownloadOperation>(handler.DownloadProgress);

    try
    {
        await download.StartAsync().AsTask(cts.Token, progressCallback);       
    }
    catch (Exception ex)
    {
        var errorCode = BackgroundTransferError.GetStatus(ex.HResult);
        toast = handler.MakeToast("Download failed", selectedAsset.name, TextFormatter.CamelToHumanCase(errorCode.ToString()), 12);
        toast.Group = "downloadFailedTag";
        ToastNotificationManager.CreateToastNotifier().Show(toast);

        return;
    }
    finally
    {
        ToastNotificationManager.History.Remove("downloadStartedTag");
    }   
}

创建toast的方法：

public ToastNotification MakeToastWithButtons(string heading, string line1, string button1, string button2)
{
    ToastVisual visual = new ToastVisual()
    {
        BindingGeneric = new ToastBindingGeneric()
        {
            Children =
            {
                new AdaptiveText() {Text = heading},
                new AdaptiveText() {Text = line1},
            }
        }
    };

    ToastActionsCustom actions = new ToastActionsCustom()
    {
        Buttons =
        {
            new ToastButton("Open", new QueryString()
            {
                { "action", "open" }
                //maybe file path can be given here in some argument

            }.ToString())
            {
                ActivationType = ToastActivationType.Foreground
            },

            new ToastButton("Dismiss", new QueryString()
            {
                { "action", "dismiss" }
                //more details about the file can be given here

            }.ToString())
            {
                ActivationType = ToastActivationType.Background
            }                        
        }

    };

    ToastContent toastContent = new ToastContent()
    {
        Visual = visual,
        Actions = actions,

        // Arguments when the user taps body of toast
        Launch = new QueryString()
        {
            { "action", "nothing" }
        }.ToString()
    };

    // And create the toast notification
    var toast = new ToastNotification(toastContent.GetXml());
    toast.ExpirationTime = DateTime.Now.AddDays(2);
    toast.Group = "DownloadCompleteGroup";

    return toast;
}

Answer 1

一种方法是将后台下载创建的destinationFile存储在FutureAccessList中，这将为您提供一个token，您可以将其添加到toast的有效负载数据：

// using Windows.Storage.AccessCache;
string token = StorageApplicationPermissions.FutureAccessList.Add(destinationFile);
// add the token to your toast payload

然后，当用户单击toast时，您可以兑换token以取回文件：

var file = await StorageApplicationPermissions.FutureAccessList.GetFileAsync(token);

现在你可以对这个文件做一些事情了。请注意，令牌是“永远”有效的--只要文件存在于磁盘上，令牌就会在应用程序重启甚至重启后工作。

处理完文件后(包括下载失败或用户取消等情况)您应该从FutureAccessList中删除该标记，以便列表不会被填满：

StorageApplicationPermissions.FutureAccessList.Remove(token);

这意味着您可能希望将令牌保存在应用程序的设置中，以防用户忽略toast。