Placing a Call with the PhoneCallTask

The phone call task is used to launch the built-in Phone app and displays the specified phone number and display name.

The following example demonstrates how to launch the phone call task:

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PhoneCallTask phoneCallTask = new PhoneCallTask
                                        {
                                            DisplayName = "Alan Turing",
                                            PhoneNumber = "882960"
                                        };
phoneCallTask.Show();

If the PhoneCallTask.PhoneNumber is a null or empty string, calling the PhoneCallTask.Show method has no effect. If the PhoneCallTask.PhoneNumber has an invalid format, the Phone app prompts the user when the call is being made.

The PhoneCallView allows the user to enter a telephone number and place a call to that number when a button is tapped.

A Place Call button in the view is bound to the viewmodel’s CallCommand.

The callCommand field is instantiated in the PhoneCallViewModel constructor. When executed, the callCommand creates a new PhoneCallTask and sets its PhoneNumber property with the text supplied by a TextBox in the view, as shown:

Click here to view code image

public PhoneCallViewModel() : base("Phone Call Tasks")
{
    callCommand = new DelegateCommand(
        delegate
            {
                PhoneCallTask phoneCallTask = new PhoneCallTask
                                             {
                                                 DisplayName = "someone",
                                                 PhoneNumber = phoneNumber
                                             };
                phoneCallTask.Show();
            });
}

Figure 14.14 shows the PhoneCallView page.

FIGURE 14.14 PhoneCallView page.

When the PhoneCallTask.Show method is called, the Phone application is launched, which deactivates the sample application but leaves the sample app’s UI visible in the background (see Figure 14.15).

FIGURE 14.15 The built-in Phone app is superimposed on the sample application.