How to open pdf file in Windows Phone 8?
You have to use the LaunchFileAsync method of Launcher class. Example: // Access the file. StorageFile pdfFile = await Windows.ApplicationModel.Package.Current.InstalledLocation.GetFileAsync(“file.pdf”); // Launch the pdf file. Windows.System.Launcher.LaunchFileAsync(pdfFile); You will find more info here: Auto-launching apps using file and URI associations for Windows Phone 8