音频文件的 FileSavePicker 在 Windows Phone 8.1 通用应用程序中不起作用

Question

我试过下面的代码，音频文件正在保存但它显示 0 字节，我试了很多如果有人知道这个请帮助我...

WP8.1 通用应用程序

Mainpage.cs中的代码：

private async void pick_Click(object sender, RoutedEventArgs e)
        {
            string path = @"Assets\Audio\DeviPrasad.mp3";
            StorageFolder folder = Windows.ApplicationModel.Package.Current.InstalledLocation;
            StorageFile file = await folder.GetFileAsync(path);

            var st =await file.OpenAsync(Windows.Storage.FileAccessMode.Read);

            var size = st.Size;

            FileSavePicker savePicker = new FileSavePicker();
            //savePicker.SuggestedStartLocation = PickerLocationId.DocumentsLibrary;
            savePicker.SuggestedSaveFile = file;
            savePicker.FileTypeChoices.Add("MP3", new List<string>() { ".mp3" });
            savePicker.ContinuationData.Add("SourceSound", path);
            savePicker.SuggestedFileName = "DeviPrasad";

            savePicker.PickSaveFileAndContinue();            
        }

internal async void ContinueFileOpenPicker(FileSavePickerContinuationEventArgs e)
        {
            var file = e.File;
            var ff= file.Properties;
            if(file!=null)
            {
                CachedFileManager.DeferUpdates(file);                  
                await FileIO.WriteTextAsync(file, file.Name);                    
                FileUpdateStatus status = await CachedFileManager.CompleteUpdatesAsync(file);
            }
        }

App.xaml.cs 中的代码：

protected async override void OnActivated(IActivatedEventArgs args)
        {
            var root = Window.Current.Content as Frame;
            var mainPage = root.Content as MainPage;
            if (mainPage != null && args is FileSavePickerContinuationEventArgs)
            {
                mainPage.ContinueFileOpenPicker(args as FileSavePickerContinuationEventArgs);
            }
        }

Answer 1

FileSavePicker 不会帮助您将文件内容写入或复制到目的地。

实际上，我认为您只是简单地从某个地方复制了以下代码，但并不完全知道它在做什么。

await FileIO.WriteTextAsync(file, file.Name);

这是向文件写入内容，似乎来自处理 txt 文件的样本。对于您的情况，我们需要做以下事情：

在pick_Click事件中将源文件路径添加到ContinuationData。将代码更改为： savePicker.ContinuationData.Add("SourceSound", file.Path);

读取ContinueFileOpenPicker中的源文件路径和目标文件写入如下内容：

    var file = e.File;
    string soundPath = (string)e.ContinuationData["SourceSound"];
    //var ff = file.Properties;

    if (file != null)
    {
        CachedFileManager.DeferUpdates(file);

        StorageFile srcFile = await StorageFile.GetFileFromPathAsync(soundPath);

        await srcFile.CopyAndReplaceAsync(file);

        FileUpdateStatus status = await CachedFileManager.CompleteUpdatesAsync(file);
    }

音频文件的 FileSavePicker 在 Windows Phone 8.1 通用应用程序中不起作用

FileSavePicker for Audio file is not working in Windows Phone 8.1 Universal Apps

c#

windows-phone-8.1

win-universal-app