Guidelines for print-capable Windows Store apps

You must register an event handler that runs when the app is ready to print.

Your PrintTaskRequested event handler should do the minimal amount of work possible to create the print task. Save more expensive work for when the PrintTaskSourceRequestedHandler is called to retrieve the printable content.

You should unregister the event handler when your app could not print.

When you unregister the event handler, this lets Windows know that your app cannot print at the present time. This ensures that the print flow runs smoothly and doesn’t fail due to a lack of content to print.

Don't use a print button in your app unless there's no other choice.

This ensures that the users invoke the print experience through the Devices Charm.

If printing is the natural completion of a particular workflow, it is appropriate to add an in-app print button at an appropriate location. For example, a user might expect to see a button to printing a boarding pass after an airline check-in workflow and using the print charm might not complicate the interaction.

You should keep error messages to two lines or less.

When a user makes an invalid entry in the print preview window, you can display an error message to alert the user about the invalid entry and the corrective action. We recommend that this information take up no more than two lines of text.

You should debug issues in your app.

For more information about debugging issues in your app, download the white paper Developing Windows Store device apps for printers.

You should not change the order of the settings shown in the print window unless it is necessary.

The order of the settings shown to the user is customizable. However, to maintain consistency in the experience, you are encouraged to retain the default order of the settings and add more settings to the list if necessary.

For example, the Copies settings are listed first in the default print experience, and users expect this listing order in your app’s print experience too.

You should not add more printer settings to the print window unless it is necessary.

Some printer settings and their behavior can be specific to the printer. It is better for the printer manufacturer to handle the addition of such settings.

If the printer manufacturer made printer-specific settings available for your printer, then users of your app can click More Settings in the print window to invoke the Windows Store device app that displays those additional settings (if this Windows Store device app has been installed).