xwt/Xwt.WPF/Xwt.WPFBackend/TextEntryBackend.cs

// 
// TextEntryBackend.cs
//  
// Author:
//       Eric Maupin <ermau@xamarin.com>
// 
// Copyright (c) 2012 Xamarin, Inc.
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using Xwt.Backends;
using Xwt.WPFBackend.Utilities;

namespace Xwt.WPFBackend
{
	public class TextEntryBackend
		: WidgetBackend, ITextEntryBackend
	{
		bool multiline;

		PlaceholderTextAdorner Adorner {
			get; set;
		}
		public TextEntryBackend()
		{
			Widget = new ExTextBox { IsReadOnlyCaretVisible = true };
			Adorner = new PlaceholderTextAdorner (TextBox);
			TextBox.Loaded += delegate {
				var layer = AdornerLayer.GetAdornerLayer (TextBox);
				if (layer != null)
					layer.Add (Adorner);
			};
			TextBox.VerticalContentAlignment = VerticalAlignment.Center;
		}

		protected override double DefaultNaturalWidth
		{
			get { return -1; }
		}

		public virtual string Text
		{
			get { return TextBox.Text; }
			set { TextBox.Text = value; }
		}

		public virtual Alignment TextAlignment
		{
			get { return DataConverter.ToXwtAlignment (TextBox.TextAlignment); }
			set { TextBox.TextAlignment = DataConverter.ToTextAlignment (value); }
		}

		public string PlaceholderText
		{
			get { return Adorner.PlaceholderText; }
			set { Adorner.PlaceholderText = value; }
		}

		public bool ReadOnly
		{
			get { return TextBox.IsReadOnly; }
			set { TextBox.IsReadOnly = true; }
		}

		public bool ShowFrame
		{
			get { return TextBox.ShowFrame; }
			set { TextBox.ShowFrame = value; }
		}

		public int CursorPosition {
			get {
				return TextBox.SelectionStart;
			}
			set {
				TextBox.SelectionStart = value;
			}
		}

		public int SelectionStart {
			get {
				return TextBox.SelectionStart;
			}
			set {
				TextBox.Focus();
				TextBox.Select(value, SelectionLength);
			}
		}

		public int SelectionLength {
			get {
				return TextBox.SelectionLength;
			}
			set {
				TextBox.Focus();
				TextBox.Select(SelectionStart, value);
			}
		}

		public string SelectedText {
			get {
				return TextBox.SelectedText;
			}
			set {
				TextBox.SelectedText = value;
			}
		}

		public bool MultiLine {
			get { return multiline; }
			set {
				if (multiline != value) {
					multiline = value;
					if (multiline) {
						TextBox.VerticalContentAlignment = VerticalAlignment.Top;
						TextBox.AcceptsReturn = true;
						TextBox.TextWrapping = TextWrapping.Wrap;
					} else {
						TextBox.VerticalContentAlignment = VerticalAlignment.Center;
						TextBox.AcceptsReturn = false;
						TextBox.TextWrapping = TextWrapping.NoWrap;
					}
				}
			}
		}

		public override void EnableEvent (object eventId)
		{
			base.EnableEvent (eventId);

			if (eventId is TextEntryEvent)
			{
				switch ((TextEntryEvent)eventId)
				{
					// TODO: Should we ignore this for placeholder changes?
					case TextEntryEvent.Changed:
						TextBox.TextChanged += OnTextChanged;
						break;
					case TextEntryEvent.Activated:
						TextBox.KeyDown += OnActivated;
						break;
					case TextEntryEvent.SelectionChanged:
						TextBox.SelectionChanged += OnSelectionChanged;
						break;
				}
			}
		}

		public override void DisableEvent (object eventId)
		{
			base.DisableEvent (eventId);

			if (eventId is TextEntryEvent)
			{
				switch ((TextEntryEvent)eventId)
				{
					case TextEntryEvent.Changed:
						TextBox.TextChanged -= OnTextChanged;
						break;
					case TextEntryEvent.Activated:
						TextBox.KeyDown -= OnActivated;
						break;
					case TextEntryEvent.SelectionChanged:
						TextBox.SelectionChanged -= OnSelectionChanged;
						break;
				}
			}
		}

		protected ExTextBox TextBox
		{
			get { return (ExTextBox) Widget; }
		}

		protected new ITextEntryEventSink EventSink {
			get { return (ITextEntryEventSink)base.EventSink; }
		}
		
		private void OnActivated(object sender, System.Windows.Input.KeyEventArgs e)
		{
			if (e.Key == System.Windows.Input.Key.Enter || e.Key == System.Windows.Input.Key.Return)
				Context.InvokeUserCode (EventSink.OnActivated);
		}

		private void OnTextChanged (object s, TextChangedEventArgs e)
		{
			Context.InvokeUserCode (EventSink.OnChanged);
		}

		private void OnSelectionChanged (object s, EventArgs e)
		{
			Context.InvokeUserCode (EventSink.OnSelectionChanged);
		}
	}
}