PrintTask Class

Definition

public ref class PrintTask sealed

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
class PrintTask final

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
public sealed class PrintTask

Public NotInheritable Class PrintTask

Inheritance

Object Platform::Object IInspectable PrintTask

Attributes

ContractVersionAttribute MarshalingBehaviorAttribute

Windows requirements

Remarks

The PrintTask object represents a printing operation for UWP apps. The app is responsible for creating a PrintTask that is requested via the PrintTaskRequested event on the PrintManager object. To create PrintTask you must provide the name for the task and a PrintTaskSourceRequestedHandler delegate which is called when the user is ready to begin printing.

If the user decides not to print the task, the task may be completed without ever requesting the document source.

PrintTask contains a reference, in the form of the Source property, to the Print Document Source provided by the app. This object must support the IPrintDocumentSource interface.

In addition PrintTask contains an Options property which holds a reference to the PrintTaskOptions object. The PrintTaskOptions object provides access to details about the desired format of the printed content. PrintTaskOptions also provides methods which allow aspects of the print user experience to be modified. For example, PrintTaskOptions allows the app to define which of the supported options appear on the initial page of the print experience.

A print task goes through a specific set of states after its creation, and these changes in state can be used by an app to provide feedback to the user. Most of the state transitions are represented in the events that are raised by PrintTask. The print task is created in response to the PrintTaskRequested event on the PrintManager using the CreatePrintTask method on the PrintTaskRequest object. At this point the print task cannot be printed, since the content to print has not yet been provided. Typically a PrintTaskRequested event is raised when the user clicks on the Devices charm or an application initiates printing via the ShowPrintUIAsync method on the PrintManager.

Once the system determines that the task will be printed, the PrintTaskSourceRequestedHandler delegate is called to actually retrieve a reference to the Document Source object. At this point PrintTask is fully initialized. If the user decides not to complete the printing represented by the PrintTask object, the completion event is raised with a completion type of abandoned.

Upon initialization the printing user experience is responsible for helping the user select the different attributes, such as paper size or duplex, for the printed content. When the print window initialization is almost complete, PrintTask raises the Previewing event. This is when the user is now able to manipulate the contents of the PrintTaskOptions object via the print window. The user may change the values of the settings at any time during the Preview stage, and this must be taken into consideration the next time an app paginates the content. The PrintTaskOptions object provides basic functionality for retrieving the values of the print settings. For more advanced control of the print options, see PrintTaskOptionDetails. Again the user may cancel this operation which will result in a completion event being raised with a completion type of cancelled.

When the user chooses to actually initiate printing by pressing Print in the print window, for example, the print task transitions from Previewing to the Submitting state, and the Submitting event is raised. The print document source is then passed a MakeDocument command and the process of submitting pages to the print subsystem begins. While pages are being submitted, the Progressing event is raised. An app may choose to use the information in the progressing event to let the user know how much content remains to be printed. Once the process of submitting the document to the print subsystem is complete, PrintTask raises the Completion event. This event indicates whether the job was submitted successfully, canceled, or failed during the submission process.

Here is a code snippet from the UWP print sample that shows how to indicate the order in which the default print settings should be displayed:

protected override void PrintTaskRequested(PrintManager sender, PrintTaskRequestedEventArgs e)
{
    PrintTask printTask = null;
    printTask = e.Request.CreatePrintTask("C# Printing SDK Sample", sourceRequestedArgs =>
    {
        IList<string> displayedOptions = printTask.Options.DisplayedOptions;

        // Choose the printer options to be shown.
        // The order in which the options are appended determines the order in which they appear in the UI
        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);

        // Preset the default value of the printer option
        printTask.Options.MediaSize = PrintMediaSize.NorthAmericaLegal;

        // Print Task event handler is invoked when the print job is completed.
        printTask.Completed += async (s, args) =>
        {
            // Notify the user when the print operation fails.
            if (args.Completion == PrintTaskCompletion.Failed)
            {
                await scenarioPage.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
                {
                    MainPage.Current.NotifyUser("Failed to print.", NotifyType.ErrorMessage);
                });
            }
        };

        sourceRequestedArgs.SetSource(printDocumentSource);
    });
}

To see the complete listing for this, and other printing scenarios using PrintTask, see Printing and the UWP print sample.

Version history

Properties

Events

Applies to

See also

• PrintManager
• Printing