Creating Tabbed Applications

新建一个空工程，如图

新建类

using System;
using UIKit;

namespace TabbedApplication
{
	public class TabController : UITabBarController
	{
		UIViewController tab1,tab2,tab3;

		public TabController ()
		{
			tab1 = new UIViewController();
			tab1.Title = "Green";
			tab1.View.BackgroundColor = UIColor.Green;
			tab1.TabBarItem = new UITabBarItem (UITabBarSystemItem.Favorites, 0);

			tab2 = new UIViewController();
			tab2.Title = "Orange";
			tab2.View.BackgroundColor = UIColor.Orange;
			tab2.TabBarItem.Image = UIImage.FromFile ("second.png");
			tab2.Title = "Second";

			tab3 = new UIViewController();
			tab3.Title = "Red";
			tab3.View.BackgroundColor = UIColor.Red;
			tab3.TabBarItem.BadgeValue = "Hi";
			var tabs = new UIViewController[] {
				tab1, tab2, tab3
			};

			ViewControllers = tabs;
		}
	}
}

　　修改 AppDelegate.cs

using System;
using System.Collections.Generic;
using System.Linq;

using Foundation;
using UIKit;

namespace TabbedApplication
{
	// The UIApplicationDelegate for the application. This class is responsible for launching the
	// User Interface of the application, as well as listening (and optionally responding) to
	// application events from iOS.
	[Register ("AppDelegate")]
	public partial class AppDelegate : UIApplicationDelegate
	{
		// class-level declarations
		UIWindow window;
		TabController tabController;
		//
		// This method is invoked when the application has loaded and is ready to run. In this
		// method you should instantiate the window, load the UI into it and then make the window
		// visible.
		//
		// You have 17 seconds to return from this method, or iOS will terminate your application.
		//
		public override bool FinishedLaunching (UIApplication app, NSDictionary options)
		{
			// create a new window instance based on the screen size
			window = new UIWindow (UIScreen.MainScreen.Bounds);

			// If you have defined a root view controller, set it here:
			// window.RootViewController = myViewController;
			tabController=new TabController();
			window.RootViewController = tabController;
			// make the window visible
			window.MakeKeyAndVisible ();

			return true;
		}
	}
}

　　运行程序