CP Vanity for Windows Phone 7

using System;
using System.Windows;
using CPVanity.ViewModel;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;

namespace CPVanity
{
    /// <summary>
    /// Description for ImagePage.
    /// </summary>
    public partial class ImagePage : PhoneApplicationPage 
    {
        /// <summary>
        /// Initializes a new instance of the ImagePage class.
        /// </summary>
        public ImagePage()
        {
            InitializeComponent();
        }

        private void ApplicationBarIconButton_Click(object sender, EventArgs e)
        {
            string button = ((IApplicationBarMenuItem)sender).Text;
            var vm = DataContext as MainViewModel;

            if (button == "save" && vm != null)
            {
                try
                {
                    vm.Save(_image.Source);
                    MessageBox.Show("Image saved");
                }
                catch (Exception ex)
                {
                    MessageBox.Show("There was an error saving the image - " + ex.Message);
                }
            }             
        }
    }
}