ViewModel.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Collections.ObjectModel;
using Microsoft.WindowsAPICodePack.Shell;
using Microsoft.WindowsAPICodePack.Dialogs;
using System.Windows;
using System.IO;
using System.ServiceProcess;

namespace HTMLtoXAML
{
	class ViewModel : INotifyPropertyChanged
	{
		public ViewModel()
		{
			FilePath = "C:/Users/lexaz/Desktop/test.html";
		}
		public Model model = new Model();
		bool let = false;
		public event EventHandler<EventArgs> OnFileUpdate;
		public FileWatcher fw = new FileWatcher();
		public Interpreter interpreter = new Interpreter();
		private Uri webFilePath;
		public Uri WebFilePath
		{
			get { return webFilePath; }
			set
			{
				webFilePath = value;
				OnPropertyChanged("WebFilePath");
			}
		}
		private string filePath;
		public string FilePath
		{
			get { return filePath;}
			set
			{
				filePath = value;
				WebFilePath = new Uri(String.Format("file:///" + value));
				OnPropertyChanged("FilePath");
			}
		}
		
		private DefaultDialogService dialogService = new DefaultDialogService();

		private string bgcolor = "#FF00AB5E";
		public string bgColor
		{
			get { return bgcolor; }
			set
			{
				bgcolor = value;
				OnPropertyChanged("bgColor");
			}
		}
		private string btntext = "Start";
		public string btnText
		{
			get { return btntext; }
			set
			{
				btntext = value;
				OnPropertyChanged("btnText");
			}
		}

		private RelayCommand openFile;
		public RelayCommand OpenFile
		{
			get
			{
				return openFile ??
				  (openFile = new RelayCommand(obj =>
				  {
					  try
					  {
						  if (dialogService.OpenFileDialog() == true)
						  {
							  FilePath = dialogService.FilePath;
						  }
					  }
					  catch (Exception ex)
					  {
						  dialogService.ShowMessage(ex.Message);
					  }
				  }));
			}
		}
		public FileSystemWatcher watcher;
		void funcChangedHandler(object sender, FileSystemEventArgs e)
		{
			if (let == false)
			{
				if (e.Name == Path.GetFileName(FilePath))
				{
					MessageBox.Show("File has updated!");
					interpreter.ReadAndWrite(FilePath);
				}
				let = true;
			}
			else
			{
				let = false;
			}
			
		}



		private RelayCommand startWatcher;
		public RelayCommand StartWatcher
		{
			get
			{
				return startWatcher ??
				  (startWatcher = new RelayCommand(obj =>
				  {
					  if (watcher != null)
						  return;
					  bgColor = "#FFAB0000";
					  btnText = "Stop";
					  try
					  {
						  watcher = new FileSystemWatcher(Path.GetDirectoryName(filePath));
						  watcher.NotifyFilter = NotifyFilters.LastWrite;
						  watcher.Changed += new FileSystemEventHandler(funcChangedHandler);
						  watcher.EnableRaisingEvents = true;
					  }
					  catch (Exception ex)
					  {
						  dialogService.ShowMessage(ex.Message);
					  }
				  }));
			}
		}
		private RelayCommand stopWatcher;
		public RelayCommand StopWatcher
		{
			get
			{
				return stopWatcher ??
				  (stopWatcher = new RelayCommand(obj =>
				  {
					  if(watcher == null)
						  return;
					  bgColor = "#FF00AB5E";
					  btnText = "Start";
					  try
					  {
						  watcher.Changed -= funcChangedHandler;
						  watcher.Dispose();
						  watcher = null;
					  }
					  catch (Exception ex)
					  {
						  dialogService.ShowMessage(ex.Message);
					  }
				  }));
			}
		}

		public event PropertyChangedEventHandler PropertyChanged;
		public void OnPropertyChanged([CallerMemberName]string prop = "")
		{
			if (PropertyChanged != null)
				PropertyChanged(this, new PropertyChangedEventArgs(prop));
		}
	}
}