How can I show an pdf file in xamarin pcl uwp that is outside my instal folder?

Question

Hy, I\'m working in a Xamarin PCL project with the platforms Android and UWP. As a feature the user should be able to open

Answer 1

I know now why. Because I'm developing a UWP application and I want to access a file outside my instal folder. This location is

You have use ms-appx-web: uri scheme as your pdf file access path. Actually, your pdf path is C:\Users\User\AppData\Local\Packages\PDFTest.UWP_v4j5n0js0cwst\LocalState\ that stored in the app's local folder. So the file will not be accessed.

I have also tested with "ms-appdata:///local/" uri scheme to access the pdf file base on your project. Unfortunately, It can't be recognised by viewer.js.

And then, I tried to convert pdf file into Base64String then opening it by calling the openPdfAsBase64 JS function in the viewer.js.

private async Task OpenAndConvert(string FileName) 
{
    var folder = ApplicationData.Current.LocalFolder;
    var file = await folder.GetFileAsync(FileName);
    var filebuffer = await file.OpenAsync(FileAccessMode.Read);
    var reader = new DataReader(filebuffer.GetInputStreamAt(0));
    var bytes = new byte[filebuffer.Size];
    await reader.LoadAsync((uint)filebuffer.Size);
    reader.ReadBytes(bytes);
    return Convert.ToBase64String(bytes);  
}

Usage

protected  override void OnElementChanged(ElementChangedEventArgs e)
{
    base.OnElementChanged(e);
    if (e.NewElement != null)
    {   
        Control.Source = new Uri("ms-appx-web:///Assets/pdfjs3/web/viewer.html");
        Control.LoadCompleted += Control_LoadCompleted;
    }
}

private async void Control_LoadCompleted(object sender, Windows.UI.Xaml.Navigation.NavigationEventArgs e)
{
    CustomWebView pdfView = Element as CustomWebView;
    if (string.IsNullOrEmpty(pdfView?.Filename)) return;

    var ret = await OpenAndConvert(pdfView?.Filename);       

    var obj = await Control.InvokeScriptAsync("openPdfAsBase64", new[] { ret });
}

You could use this viewer.js that was added openPdfAsBase64 method.

Got hints following: How to embed the PDFjs into your C# Project.