Selecting an Email Address with the EmailAddressChooserTask

The email address chooser task launches the Windows Phone Contacts application and allows the user to select a contact. When the user completes the task, the Completed event is raised, and the event handler receives an EmailResult object that exposes a string containing the selected contact’s email address.

The EmailAddressChooserTask should be defined as a field in your class, like so:

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readonly EmailAddressChooserTask emailAddressChooserTask
                                     = new EmailAddressChooserTask();

Subscribe to the EmailAddressChooserTask.Completed event within your class constructor, as shown:

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emailAddressChooserTask.Completed
   += new EventHandler<EmailResult>(HandleEmailAddressChooserTaskCompleted);

Use the Show method of the EmailAddressChooserTask to launch the built-in Contacts app. When the task completes, the handler receives an EmailResult object, as shown:

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void HandleEmailAddressChooserTaskCompleted(object sender, EmailResult e)
{
    if (e.TaskResult == TaskResult.OK)
    {
        ToAddress = e.Email;
    }
    else if (e.Error != null)
    {
        Message = "Unable to choose email address. " + e.ToString();
    }
    else if (e.TaskResult == TaskResult.Cancel)
    {
        Message = "Cancelled";
    }
}

FIGURE 14.5 The EmailView page.

The viewmodel contains a public property of type ICommand called ChooseRecipientCommand. The view’s Choose Email button is bound to the command.

When the ChooseRecipientCommand is executed, the Show method of the emailAddressChooserTask is called. This behavior is defined in the viewmodel constructor, as shown:

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public EmailViewModel() : base("Email")
{
    emailAddressChooserTask.Completed
                                += HandleEmailAddressChooserTaskCompleted;

    chooseRecipientCommand = new DelegateCommand(
        obj => emailAddressChooserTask.Show());
...
}

When the EmailAddressChooserTask.Show method is called, the built-in Contacts application is launched (see Figure 14.6).

FIGURE 14.6 The Windows Phone Contacts application.

The result returned by the Contacts app is used by an EmailComposeTask, which is presented in the next section.