private void OpenFileExecute(string fileName)
        {
            if (fileName == "")
            {
                MessageBox.Show("Enter a name for the file in the text box File Name", "Warning", MessageBoxButton.OK,
                                MessageBoxImage.Exclamation);
            }
            else
            {
                try
                {
                    _fileName = fileName;
                    Agents tempAgents = new Agents();
                    tempAgents.Clear();

                    //using (var stream = new FileStream(_fileName, FileMode.Open))
                    using (var stream = new StreamReader(_fileName))
                    {
                        XmlSerializer XML = new XmlSerializer(typeof(Agents));
                        tempAgents = (Agents)XML.Deserialize(stream);
                        stream.Close();
                    }

                    Clear();
                    foreach (var agent in tempAgents)
                    {
                        Add(agent);
                    }
                    NotifyPropertyChanged("Count");
                }
                catch (Exception e)
                {
                    MessageBox.Show("There is no file with the given name", "Error", MessageBoxButton.OK, MessageBoxImage.Error);
                    //Console.WriteLine(e);
                    //throw;
                }
            }
        }