在 Windows Phone 8 上启动 PDF 阅读器 [英] Launching PDF reader on windows phone 8

问题描述

我正在尝试使用以下代码启动 pdf 阅读器，但它不起作用.有人可以帮我吗?

I'm trying to launch pdf reader with the code below but it does not work. Can somebody help me?

    private async Task<StorageFile> WriteData(string fileName, byte[] data)
    {
        StorageFolder folder = ApplicationData.Current.LocalFolder;

        StorageFile file = await folder.CreateFileAsync(fileName, CreationCollisionOption.ReplaceExisting);

        using (Stream s = await file.OpenStreamForWriteAsync())
        {
            await s.WriteAsync(data, 0, data.Length);
            s.Close();
        }

        return file;
    }

    private async Task<bool> OpenPdf(StorageFile file) 
    {

        var uri = new Uri(file.Path, UriKind.RelativeOrAbsolute);
        bool result = await Windows.System.Launcher.LaunchUriAsync(uri);

        return result;
    }

    private async void FetchPdf() {
         // Fetch pdf bytes to network
         //....
         StorageFile file = await WriteData("test.pdf", data);

         if (file != null) {
            bool result = await OpenPdf(file);     
            if (result)
              Debug.WriteLine("Success");
            else 
              Debug.WriteLine("Cannot open pdf file.");
         }
    }

result 始终为 false，因此不显示启动器.

result is always false and so launcher is not presented.

我使用 LaunchUriAsync 是因为 LaunchFileAsync 未在 Windows Phone 上实现.

I used LaunchUriAsync because LaunchFileAsync is not implemented on Windows Phone.

推荐答案

LaunchUriAsync 根据 文档.如果调用它会抛出异常

LaunchUriAsync isn't supported on Windows Phone 8 per the documentation. It throws an exception if called

您可以使用 Windows.System.Launcher.LaunchFileAsync 来启动 StorageFile.

You can use Windows.System.Launcher.LaunchFileAsync to launch a StorageFile.

例如，此代码有效(假设项目中有一个名为 "metro.pdf" 的文件，其中 Build Action 设置为 Content>，将 Copy to Output Directory 设置为 Copy if Newer).

This code works for example (assming there's a file called "metro.pdf" in the project, with the Build Action set to Content, with Copy to Output Directory set to Copy if Newer).

var installedLocation = Windows.ApplicationModel.Package.Current.InstalledLocation;
var assets = await installedLocation.GetFolderAsync("Assets");
var pdf = await assets.GetFileAsync("metro.pdf");
Windows.System.Launcher.LaunchFileAsync(pdf);

这篇关于在 Windows Phone 8 上启动 PDF 阅读器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！