Printing from Your VB 2013 App in Windows 8.1

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Introduction

Hello and welcome to my article. Today, I will demonstrate how simple, yet complicated, printing is inside your Windows 8.1 apps.

Design

Start Visual Studio 2013 and create a new VB Windows Store application. If you are uncertain on just how to get started, feel free to read the following articles:

• 25 Tools You Can Use for Windows 8 Store App Development
• How to Make Toast Notifications in your Windows Store Application with VB
• Windows 8/8.1 ApplicationDataContainers and VB

Once the project has been created, add the following objects to your page:

• A button named btnPrint with a Content value of Print Charms
• A button named btnPrintInApp with a Content value of Print in App

Before I jump in with the code for these buttons, I must first explain how to add a new PrintPage to your application. This PrintPage can be used as a print preview for your application. Add a new Page now by following the next steps:

1. Click Project.
2. Click Add New Item.
3. Click Blank Page.
4. Click Add after you have given it a descriptive name, such as PrintPage.xaml.

PrintPage.xaml.vb

Add the following Namespaces to this page:

Imports System
Imports Windows.Graphics.Printing
Imports Windows.UI.Xaml.Printing

These namespaces help with printing and print settings. Add the following fields to your page:

Protected Const MarginLeft As Double = 0.075

Protected Const MarginTop As Double = 0.03

At first glance, you can already figure out what each object’s purpose would be. That is why it is so important to properly name your objects. The first two objects deal with the page’s left and top margins respectively.

Add the following to your printing page:

Protected Sub PreparePrintContent()
End Sub

Protected Read-Only Property Printing Root() As Canvas
   Get
      Return TryCast(FindName("_printingRoot"), Canvas)
   End Get
End Property

Here we allow this document to be printed and specify where to begin.

MainPage.xaml.vb

Add the following Imports to your page:

Imports Windows.Graphics.Printing
Imports Windows.UI.Xaml.Printing

There are two Imports. The first import is to import the built-in Windows Printing element. The next one is specifically for Windows Store apps. Add the following fields to your page:

Private Registered As Boolean = False

Private pp As New PrintPage
Protected printDoc As PrintDocument = Nothing

Protected printDocSource As IPrintDocumentSource = Nothing

Friend printPreviewPages As List(Of UIElement) = Nothing

Protected firstPage As FrameworkElement

These objects identify the printable document, its source, as well as the print preview. A very important object to talk about is the first object, Registered. This variable will either tell us if a document that is registered is to be printed or not. A document must be registered for printing; otherwise, it will not print. You must also remember to add the necessary application permissions to permit printing capabilities. If you are uncertain on how to do that, refer to the articles I listed at the beginning of this article.

In App Printing

Not much to be added here. Add this piece of code to your page:

Private Async Sub btnPrintInApp_Click(sender As Object,
   e As RoutedEventArgs) Handles btnPrintInApp.Click
   Await PrintManager.ShowPrintUIAsync()

End Sub

As simple as that. This makes use of the PrintManager object inside the Windows.Graphics.Printing Namespace. This simply shows the Printing options.

Print Charms

Add the following code:

Protected Sub PreparePrintContent()
End Sub

Protected Sub RegisterForPrinting()

   printDoc = New PrintDocument()


   printDocSource = printDoc.DocumentSource


   AddHandler printDoc.Paginate, AddressOf CreatePrintPreviewPages


   AddHandler printDoc.GetPreviewPage, AddressOf GetPrintPreviewPage


   Dim printMngr As PrintManager = PrintManager.GetForCurrentView()
   AddHandler printMngr.PrintTaskRequested, AddressOf PrintTaskRequested

    PreparePrintContent()
End Sub

Protected Sub UnregisterForPrinting()
   If printDoc Is Nothing Then
      Return
   End If

   RemoveHandler printDoc.Paginate, AddressOf CreatePrintPreviewPages
   RemoveHandler printDoc.GetPreviewPage, AddressOf GetPrintPreviewPage

   Dim printMngr As PrintManager = PrintManager.GetForCurrentView()
   RemoveHandler printMngr.PrintTaskRequested, AddressOf PrintTaskRequested


End Sub

These subs take care of registering your document to be printed, as well as unregistering it. They also allow us to set up our preview page through a call to GetPreviewPages and CreatePreviewPage, as shown next:

Protected Sub GetPrintPreviewPage(ByVal sender As Object, ByVal e As GetPreviewPageEventArgs)
   Dim printDoc As PrintDocument = CType(sender, PrintDocument)

   printDoc.SetPreviewPage(e.PageNumber, printPreviewPages(e.PageNumber - 1))
End Sub

Protected Event pagesCreated As EventHandler
Protected Sub CreatePrintPreviewPages(ByVal sender As Object, ByVal e As PaginateEventArgs)

    printPreviewPages.Clear()


   Dim printingOptions As PrintTaskOptions = (CType(e.PrintTaskOptions, PrintTaskOptions))

   Dim pageDescription As PrintPageDescription = printingOptions.GetPageDescription(0)


   If pagesCreatedEvent IsNot Nothing Then
      pagesCreatedEvent.Invoke(printPreviewPages, Nothing)
   End If

   Dim printDoc As PrintDocument = CType(sender, PrintDocument)


   printDoc.SetPreviewPageCount(printPreviewPages.Count, PreviewPageCountType.Intermediate)
End Sub

Add the PrintTaskRequested event:

Protected Sub PrintTaskRequested(ByVal sender As PrintManager, ByVal e As PrintTaskRequestedEventArgs)
   Dim printingTask As PrintTask = Nothing
   printingTask = e.Request.CreatePrintTask("Printing Example", Sub(sourceRequestedArgs)
      Dim displayedOptions As IList(Of String) = printingTask.Options.DisplayedOptions
      displayedOptions.Clear()
      displayedOptions.Add(Windows.Graphics.Printing.StandardPrintTaskOptions.Copies)
      displayedOptions.Add(Windows.Graphics.Printing.StandardPrintTaskOptions.Orientation)
      displayedOptions.Add(Windows.Graphics.Printing.StandardPrintTaskOptions.MediaSize)
      displayedOptions.Add(Windows.Graphics.Printing.StandardPrintTaskOptions.Collation)
      displayedOptions.Add(Windows.Graphics.Printing.StandardPrintTaskOptions.Duplex)
      printingTask.Options.MediaSize = PrintMediaSize.NorthAmericaLegal
      AddHandler printingTask.Completed, Async Sub(s, args)
      If args.Completion = PrintTaskCompletion.Failed Then Await
         Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
         Sub() tb1.Text = "Failed to print.")
      End If
      End Sub
      sourceRequestedArgs.SetSource(printDocSource)
   End Sub)
End Sub

Now, we have much more flexibility when trying to print  or preview a document. Add the remaining Print button’s code:

Private Sub btnPrint_Click(sender As Object, e As RoutedEventArgs) Handles btnPrint.Click
   Dim clickedButton As Button = TryCast(sender, Button)

   ' Check to see if the application is registered for printing
   If Registered Then

      UnregisterForPrinting()


      clickedButton.Content = "Register"

   Else

      RegisterForPrinting()


      clickedButton.Content = "Unregister"

   End If


   Registered = Not Registered
End Sub

Conclusion

I hope you have learned from today’s article and that you can put this new knowledge to safe use. Until next time, this is me signing off.