ios-samples/MonoCatalogSample/picker.cs

//
// The PickerViewController
//
using MonoTouch.Foundation;
using MonoTouch.UIKit;
using System.Drawing;
using System;

public partial class PickerViewController : UIViewController  {
	UIPickerView myPickerView, customPickerView;
	UIDatePicker datePickerView;
	UILabel label;
	
	public PickerViewController () : base ("PickerViewController", null)
	{
	}
	
	public override void ViewDidLoad ()
	{
		base.ViewDidLoad ();
		Title = "Picker";

		CreatePicker ();
		CreateDatePicker ();
		CreateCustomPicker ();

		// Colors
		buttonBarSegmentedControl.TintColor = UIColor.DarkGray;
		pickerStyleSegmentedControl.TintColor = UIColor.DarkGray;

		label = new UILabel (new RectangleF (20f, myPickerView.Frame.Y - 30f, View.Bounds.Width - 40f, 30f)){
			Font = UIFont.SystemFontOfSize (14),
			TextAlignment = UITextAlignment.Center,
			TextColor = UIColor.White,
			BackgroundColor = UIColor.Clear
		};
		View.AddSubview (label);
		buttonBarSegmentedControl.SelectedSegment = 0;
		datePickerView.Mode = UIDatePickerMode.Date;
	}

	public override void ViewWillAppear (bool animated)
	{
		NavigationController.NavigationBar.BarStyle = UIBarStyle.Black;
		UIApplication.SharedApplication.StatusBarStyle = UIStatusBarStyle.BlackOpaque;
		TogglePickers (buttonBarSegmentedControl);
	}

	public override void ViewWillDisappear (bool animated)
	{
		if (currentPicker != null)
			currentPicker.Hidden = true;
		NavigationController.NavigationBar.BarStyle = UIBarStyle.Default;
		UIApplication.SharedApplication.StatusBarStyle = UIStatusBarStyle.Default;
	}
	
	RectangleF PickerFrameWithSize (SizeF size)
	{
		var screenRect = UIScreen.MainScreen.ApplicationFrame;
		return new RectangleF (0f, screenRect.Height - 84f - size.Height, size.Width, size.Height);
	}

	UIView currentPicker;
	void ShowPicker (UIView picker)
	{
		if (currentPicker != null){
			currentPicker.Hidden = true;
			label.Text = "";
		}

		picker.Hidden = false;
		currentPicker = picker;
	}
	
#region Hooks from Interface Builder
	[Export ("togglePickers:")]
	public void TogglePickers (UISegmentedControl sender)
	{
		switch (sender.SelectedSegment){
		case 0: 
			pickerStyleSegmentedControl.Hidden = true;
			segmentLabel.Hidden = true;
			ShowPicker (myPickerView);
			break;

		case 1:
			pickerStyleSegmentedControl.SelectedSegment = 1;
			datePickerView.Mode = UIDatePickerMode.Date;
			pickerStyleSegmentedControl.Hidden = false;
			segmentLabel.Hidden = false;
			ShowPicker (datePickerView);
			break;

		case 2:
			pickerStyleSegmentedControl.Hidden = true;
			segmentLabel.Hidden = true;
			ShowPicker (customPickerView);
			break;
		}
	}

	[Export ("togglePickerStyle:")]
	public void TogglePickerStyle (UISegmentedControl sender)
	{
		switch (sender.SelectedSegment){
		case 0: // time
			datePickerView.Mode = UIDatePickerMode.Time;
			break;
			
		case 1: // date
			datePickerView.Mode = UIDatePickerMode.Date;
			break;
			
		case 2: // date & time
			datePickerView.Mode = UIDatePickerMode.DateAndTime;
			break;
			
		case 3: // counter
			datePickerView.Mode = UIDatePickerMode.CountDownTimer;
			break;
		}

		datePickerView.Date = NSDate.Now; //DateTime.Now;

		Console.WriteLine ("Date is: {0} {1} {2}", NSDate.Now.ToString (), ((NSDate) DateTime.Now).ToString (), DateTime.Now);
	}
#endregion
	
#region Custom picker
	public void CreateCustomPicker ()
	{
		customPickerView = new UIPickerView (RectangleF.Empty) {
			AutoresizingMask = UIViewAutoresizing.FlexibleWidth,
			Model = new CustomPickerModel (),
			ShowSelectionIndicator = true,
			Hidden = true
		};
		customPickerView.Frame = PickerFrameWithSize (customPickerView.SizeThatFits (SizeF.Empty));
		View.AddSubview (customPickerView);
	}

#endregion
	
#region Date picker
	public void CreateDatePicker ()
	{
		datePickerView = new UIDatePicker (RectangleF.Empty) {
			AutoresizingMask = UIViewAutoresizing.FlexibleWidth,
			Mode = UIDatePickerMode.Date,
			Hidden = true
		};
		datePickerView.Frame = PickerFrameWithSize (datePickerView.SizeThatFits (SizeF.Empty));
		View.AddSubview (datePickerView);
	}
#endregion

#region People picker
	
	void CreatePicker ()
	{
		//
		// Empty is used, since UIPickerViews have auto-sizing,
		// all that is required is the origin
		//
		myPickerView = new UIPickerView (RectangleF.Empty){
			AutoresizingMask = UIViewAutoresizing.FlexibleWidth,
			ShowSelectionIndicator = true,
			Model = new PeopleModel (this),
			Hidden = true
		};
		// Now update it:
		myPickerView.Frame = PickerFrameWithSize (myPickerView.SizeThatFits (SizeF.Empty));
		View.AddSubview (myPickerView);
	}

	public class PeopleModel : UIPickerViewModel {
		static string [] names = new string [] {
			"Brian Kernighan",
			"Dennis Ritchie",
			"Ken Thompson",
			"Kirk McKusick",
			"Rob Pike",
			"Dave Presotto",
			"Steve Johnson"
		};

		PickerViewController pvc;
		public PeopleModel (PickerViewController pvc) {
			this.pvc = pvc;
		}
		
		public override int GetComponentCount (UIPickerView v)
		{
			return 2;
		}

		public override int GetRowsInComponent (UIPickerView pickerView, int component)
		{
			return names.Length;
		}

		public override string GetTitle (UIPickerView picker, int row, int component)
		{
			if (component == 0)
				return names [row];
			else
				return row.ToString ();
		}

		public override void Selected (UIPickerView picker, int row, int component)
		{
			pvc.label.Text = String.Format ("{0} - {1}",
						    names [picker.SelectedRowInComponent (0)],
						    picker.SelectedRowInComponent (1));
		}
		
		public override float GetComponentWidth (UIPickerView picker, int component)
		{
			if (component == 0)
				return 240f;
			else
				return 40f;
		}

		public override float GetRowHeight (UIPickerView picker, int component)
		{
			return 40f;
		}
	}
#endregion
}