Crystal Image Toolkit: thumbnail image control and picture viewing.

using System;
using System.Windows.Forms;
using Attilan.Crystal.Controls;

namespace SimpleImageGridDemo
{
    /// <summary>
    /// Demonstrates the minimal steps required to get CrystalImageGridView running
    /// properly in your Forms applications.
    /// </summary>
    public partial class Form1 : Form
    {
        /// <summary>
        /// CrystalFileCollector object, assists in retrieving image files in a specified folder.
        /// </summary>
        private CrystalCollector _theCollector = null;

        /// <summary>
        /// Internal flag indicating whether the CrystalThumbnail thread is running in the background.
        /// </summary>
        private bool _thumbnailComplete = true;

        public Form1()
        {
            InitializeComponent();
        }


        /// <summary>
        /// Initialize the Crystal collector object.
        /// </summary>
        /// <param name="sourcePath">Source folder path where images files are located.</param>
        private void InitCollector(string sourcePath)
        {
            if (_theCollector != null)
            {
                // Stop the thumbnailer if it is currently running in the background.
                _theCollector.ThumbnailComplete -= new EventHandler(_collector_ThumbnailComplete);
                StopThumbnailer();
                _theCollector.PurgeImages();
            }
            else
                _theCollector =
                    CrystalCollectorFactory.DefaultFactory.CreateCollector(CrystalCollectorType.CrystalFileCollector);

            // If the source path is empty, and the CrystalFileCollector has
            // just been initialized, the default ImageLocation is set to MyPictures.
            if (sourcePath != string.Empty)
                _theCollector.ImageLocation = sourcePath;

            // Add the CrystalImageGridView object to the collector.
            // The collector will work with the view to draw the images.
            _theCollector.SetupView(crystalImageGridView1);
            _thumbnailComplete = false;

            // Let's subscribe to the thumbnail complete event,
            // so we will know when then background thumbnail task is done.
            _theCollector.ThumbnailComplete += new EventHandler(_collector_ThumbnailComplete);

            // Tell CrystalFileCollector to collect the images in the ImageLocation folder.
            _theCollector.CollectImages();
        }

        /// <summary>
        /// Stop the background thumbnail thread.
        /// </summary>
        /// <param name="sender">Sender object.</param>
        /// <param name="e">Event arguments.</param>
        void _collector_ThumbnailComplete(object sender, EventArgs e)
        {
            _thumbnailComplete = true;
        }

        /// <summary>
        /// Open a new folder using the folder browse dialog.
        /// </summary>
        /// <param name="sender">Object sender.</param>
        /// <param name="e">Event arguments.</param>
        private void openFolderToolStripMenuItem_Click(object sender, EventArgs e)
        {
            // Browse for a new image folder and set this into the CrystalFileCollector.
            folderBrowserDialog1.SelectedPath = _theCollector.ImageLocation;
            if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
            {
                InitCollector(folderBrowserDialog1.SelectedPath);
            }
        }

        /// <summary>
        /// Exit the application.
        /// </summary>
        /// <param name="sender">Object sender.</param>
        /// <param name="e">Event arguments.</param>
        private void exitToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        /// <summary>
        /// Stop the thumbnailer by killing the collection thread.
        /// </summary>
        protected void StopThumbnailer()
        {
            if ((_theCollector != null) && (!_thumbnailComplete))
            {
                _theCollector.StopCollection();
                _thumbnailComplete = true;
            }
        }

        /// <summary>
        /// Form close event handler.
        /// </summary>
        /// <param name="e">Event arguments.</param>
        protected override void OnFormClosing(FormClosingEventArgs e)
        {
            // Kill the thumbnailer before closing.
            StopThumbnailer();
            
            base.OnFormClosing(e);
        }

        /// <summary>
        /// Form load, initialize the collector.
        /// </summary>
        /// <param name="sender">object sender.</param>
        /// <param name="e">Event arguments.</param>
        private void Form1_Load(object sender, EventArgs e)
        {
            // Initialize the collector with no specified folder.
            // This will make the CrystalFileCollector use the MyPictures
            // folder by default.
            InitCollector(string.Empty);
        }
    }
}