How to print in UWP app?

Question

I am trying to print out something from my UWP app. Basically I've used a WebViewBrush to draw some data on to some FrameworkElement's (Windows.UI.Xaml.Shapes.Rectangle) - and I want to print one of these Rectangles on each page (one rectangle per page)

I was really hoping someone could provide a very simple example of how printing in UWP works. I have tried it myself and I am happy to provide my code, but there are honestly thousands of lines - all of which I've taken from the Microsoft GitHub examples and tried tweaking:

• https://github.com/Microsoft/Windows-universal-samples/tree/master/Samples/Printing

Honestly, those examples are too complicated I think. What I want is just a really simple way to print. I can't find any tutorials on this topic either, but I figure if someone has a small code snippet that I could get working maybe I could build on it so it will work with Rectangles (rather than what I'm doing now - taking a huge example from Microsoft and trying to figure out which parts I don't need).

Thank you. I think anyone that can answer this question in a simple way will find this will become a definitive reference point in the future - because information online about this topic is so scarce.

Answer 1

For how to print in UWP apps, you can follow the steps in Print from your app. And also refer to the Printing sample on GitHub. Following is a simple sample demonstrates how to print a rectangle on the page.

In XAML, add a print button and the rectangle to be printed.

<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto" />
        <RowDefinition />
    </Grid.RowDefinitions>
    <Button HorizontalAlignment="Center" Click="PrintButtonClick">Print</Button>
    <Rectangle x:Name="RectangleToPrint"
               Grid.Row="1"
               Width="500"
               Height="500">
        <Rectangle.Fill>
            <ImageBrush ImageSource="Assets/img.jpg" />
        </Rectangle.Fill>
    </Rectangle>
</Grid>

And in code-behind, handle the print logic.

public sealed partial class MainPage : Page
{
    private PrintManager printMan;
    private PrintDocument printDoc;
    private IPrintDocumentSource printDocSource;

    public MainPage()
    {
        this.InitializeComponent();
    }

    #region Register for printing

    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        // Register for PrintTaskRequested event
        printMan = PrintManager.GetForCurrentView();
        printMan.PrintTaskRequested += PrintTaskRequested;

        // Build a PrintDocument and register for callbacks
        printDoc = new PrintDocument();
        printDocSource = printDoc.DocumentSource;
        printDoc.Paginate += Paginate;
        printDoc.GetPreviewPage += GetPreviewPage;
        printDoc.AddPages += AddPages;
    }

    #endregion

    #region Showing the print dialog

    private async void PrintButtonClick(object sender, RoutedEventArgs e)
    {
        if (PrintManager.IsSupported())
        {
            try
            {
                // Show print UI
                await PrintManager.ShowPrintUIAsync();
            }
            catch
            {
                // Printing cannot proceed at this time
                ContentDialog noPrintingDialog = new ContentDialog()
                {
                    Title = "Printing error",
                    Content = "\nSorry, printing can' t proceed at this time.",
                    PrimaryButtonText = "OK"
                };
                await noPrintingDialog.ShowAsync();
            }
        }
        else
        {
            // Printing is not supported on this device
            ContentDialog noPrintingDialog = new ContentDialog()
            {
                Title = "Printing not supported",
                Content = "\nSorry, printing is not supported on this device.",
                PrimaryButtonText = "OK"
            };
            await noPrintingDialog.ShowAsync();
        }
    }

    private void PrintTaskRequested(PrintManager sender, PrintTaskRequestedEventArgs args)
    {
        // Create the PrintTask.
        // Defines the title and delegate for PrintTaskSourceRequested
        var printTask = args.Request.CreatePrintTask("Print", PrintTaskSourceRequrested);

        // Handle PrintTask.Completed to catch failed print jobs
        printTask.Completed += PrintTaskCompleted;
    }

    private void PrintTaskSourceRequrested(PrintTaskSourceRequestedArgs args)
    {
        // Set the document source.
        args.SetSource(printDocSource);
    }

    #endregion

    #region Print preview

    private void Paginate(object sender, PaginateEventArgs e)
    {
        // As I only want to print one Rectangle, so I set the count to 1
        printDoc.SetPreviewPageCount(1, PreviewPageCountType.Final);
    }

    private void GetPreviewPage(object sender, GetPreviewPageEventArgs e)
    {
        // Provide a UIElement as the print preview.
        printDoc.SetPreviewPage(e.PageNumber, this.RectangleToPrint);
    }

    #endregion

    #region Add pages to send to the printer

    private void AddPages(object sender, AddPagesEventArgs e)
    {
        printDoc.AddPage(this.RectangleToPrint);

        // Indicate that all of the print pages have been provided
        printDoc.AddPagesComplete();
    }

    #endregion

    #region Print task completed

    private async void PrintTaskCompleted(PrintTask sender, PrintTaskCompletedEventArgs args)
    {
        // Notify the user when the print operation fails.
        if (args.Completion == PrintTaskCompletion.Failed)
        {
            await CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, async () =>
            {
                ContentDialog noPrintingDialog = new ContentDialog()
                {
                    Title = "Printing error",
                    Content = "\nSorry, failed to print.",
                    PrimaryButtonText = "OK"
                };
                await noPrintingDialog.ShowAsync();
            });
        }
    }

    #endregion
}