The Contacts Framework provides Xamarin.iOS access to the user's contact information. Because most apps only require read-only access, this framework has been optimized for thread safe, read-only access.

For any Xamarin.iOS app that needs to adjust the values of an existing contact (or create new ones), use the NSMutableContact version of the class and its sub classes (such as CNMutablePostalAddress).

To use the built-in Contact View Controller to add a new contact, do the following:

Design your app's User Interface that will be used to call the Contact View Controller. For example, a UINavigationController to house the Contact View and a UIButton to present it:

Create a new contact and present the Contact View when the user clicks the button. For example:

using System;
using Foundation;
using Contacts;
using ContactsUI;
using UIKit;

namespace ContactAccess
{
	public partial class ViewController : UIViewController
	{
		protected ViewController (IntPtr handle) : base (handle)
		{
			
		}

		public override void ViewDidLoad ()
		{
			base.ViewDidLoad ();
		}

		partial void AddContact_TouchUpInside (UIButton sender)
		{

			// Create a new Mutable Contact (read/write)
			// and attach it to the editor
			var store = new CNContactStore ();
			var contact = new CNMutableContact ();
			var editor = CNContactViewController.FromNewContact (contact);

			// Configure editor
			editor.ContactStore = store;
			editor.AllowsActions = true;
			editor.AllowsEditing = true;

			// Display picker
			var navController = ParentViewController as UINavigationController;
			navController.PushViewController (editor, true);
		}
	}
}

Let's look at this code in detail:

1. First, it gains access to the Contact Store (CNContactStore).
2. Then it creates a new editable Contact (CNMutableContact) and attaches it to a Contact View: CNContactViewController.FromNewContact (contact).
3. Then it attaches the Contact View to the Contact Store and configures it for editing.
4. Finally, it gains access to the parent Navigation Controller (ParentViewController as UINavigationController) and presents the editor: navController.PushViewController (editor, true).

For more information, please see our Contacts and ContactUI documentation.