private async Task PerformSave(PDFDoc doc) { // Start File Picker so we can SaveAs/Export document var savePicker = new Windows.Storage.Pickers.FileSavePicker(); savePicker.FileTypeChoices.Add("PDF", new List <string> { ".pdf" }); var storageFile = await savePicker.PickSaveFileAsync(); if (storageFile != null) { await doc.SaveToNewLocationAsync(storageFile, pdftron.SDF.SDFDocSaveOptions.e_incremental); } }