C# and VB.NET Code Searcher - Using Roslyn

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;
using System.Threading;
using System.IO;

namespace RoslynCodeSearcher
{
    public class WorkspaceUpdater
    {
        private BackgroundWorker _worker;
        private CodeRepository.ProgressBarMaxUpdateHandler _progressBarMaxUpdateHandler;
        private CodeRepository.ProgressBarProgressUpdateHandler _progressBarProgressUpdateHandler;

        /// <summary>
        /// Constructor for Worker that instantiates a backgroundworker to do the work in a separate thread.
        /// </summary>
        public WorkspaceUpdater(CodeRepository.ProgressBarMaxUpdateHandler progressBarMaxUpdateHandler, CodeRepository.ProgressBarProgressUpdateHandler progressBarProgressUpdateHandler)
        {
            _progressBarMaxUpdateHandler = progressBarMaxUpdateHandler;
            _progressBarProgressUpdateHandler = progressBarProgressUpdateHandler;

            IsReady = false;
            _worker = new BackgroundWorker();
            _worker.DoWork += new DoWorkEventHandler(worker_DoWork);
            _worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
        }

        public void Start()
        {
          _worker.RunWorkerAsync();
        }

        /// <summary>
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            IsReady = true;
        }

        public static bool IsReady {get;set;}

        /// <summary>
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void worker_DoWork(object sender, DoWorkEventArgs e)
        {
            string baseDirectorySolutionsTxtPath = Paths.BaseDirectorySolutionsTxtPath;

            if (File.Exists(baseDirectorySolutionsTxtPath))
            {
                string contents = File.ReadAllText(baseDirectorySolutionsTxtPath);
                if (contents.Length > 10)
                {
                    //Put errors in front of solution files that don't exist anymore.
                    CodeRepository.FixSolutions(baseDirectorySolutionsTxtPath);
                    //Get the solutions from the solutions.txt file
                    CodeRepository.Solutions = CodeRepository.GetSolutions(baseDirectorySolutionsTxtPath);

                    CodeRepository.Workspaces = CodeRepository.GetWorkspacesParallel(CodeRepository.Solutions, _progressBarMaxUpdateHandler, _progressBarProgressUpdateHandler);

                    //Sometimes the progressbar is not completely finished after getting the workspaces.
                    //Even though I use locking.
                    //Finish it manually
                    if (_progressBarProgressUpdateHandler != null)
                    {
                        _progressBarProgressUpdateHandler(CodeRepository.SolutionCount);
                    }
                }
            }
        }
    }
}