Shows how to add a Spell Check item to the RichText context menu on WPF using a native style in Eto.Forms.

WpfSpellCheckRTF.cs

using System;
using swc = System.Windows.Controls;
using swi = System.Windows.Input;
using Eto;
using Eto.Forms;
using Eto.Drawing;

namespace TestWpfSpellCheckMenuItem
{
	class Startup
	{
		[STAThread]
		static void Main(string[] args)
		{
			bool enableSpellCheck = true;
			Style.Add<Eto.Wpf.Forms.Controls.RichTextAreaHandler>(null, h =>
			{
				h.SpellCheck = enableSpellCheck;
				var menu = new swc.ContextMenu();
				menu.Items.Add(new swc.MenuItem { Command = swi.ApplicationCommands.Cut });
				menu.Items.Add(new swc.MenuItem { Command = swi.ApplicationCommands.Copy });
				menu.Items.Add(new swc.MenuItem { Command = swi.ApplicationCommands.Paste });
				menu.Items.Add(new swc.Separator());
				var toggleSpellCheck = new swc.MenuItem
				{
					Header = "Spell Check",
					IsCheckable = true,
					IsChecked = h.SpellCheck,
					
				};
				toggleSpellCheck.Checked += (sender, e) => h.SpellCheck = enableSpellCheck = true;
				toggleSpellCheck.Unchecked += (sender, e) => h.SpellCheck = enableSpellCheck = false;
				menu.Items.Add(toggleSpellCheck);
				h.Control.ContextMenu = menu;
			});

			new Application(new Eto.Wpf.Platform()).Run(new Form
			{
				Content = new TableLayout
				{
					Padding = 10,
					Spacing = new Size(5, 5),
					Rows =
					{
						"RichTextArea with spell check context menu:",
						new RichTextArea()
					}
				}
			});
		}
	}
}