Audio Book Player

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Collections;
using System.Threading;
using System.Runtime.InteropServices;

namespace abPlayer
{
    public partial class frmFileSelector : Form
    {
        // API calls
        [DllImport("coredll.dll")]
        public static extern IntPtr GetDC(IntPtr hWnd);
        [DllImport("coredll.dll")]
        public static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);
        // treeview root name
        private const String ROOT_NAME = "My Device";
        // selected book & files are returned in these
        public ArrayList BookFiles = null;
        public String DefaultBookName = "";

        public frmFileSelector()
        {
            InitializeComponent();

            // selected book & files are returned in these
            BookFiles = new ArrayList();
        }
        // override the showdialog so we can do some prep
        // first time only - we scan the directories and build the treeview
        // on subsequnt call we initialize view
        public new DialogResult ShowDialog()
        {
            // reset book name & files
            BookFiles.Clear();
            DefaultBookName = "";
            // clear files
            lvw.Items.Clear();
            // erase book count display
            spl.Refresh();
            chkRec.Checked = false;
            // no treeview entries? - this is the first call - build treeview
            if (tvw.Nodes.Count == 0)
            {
                // this may take time - show wait cursor
                Cursor.Current = Cursors.WaitCursor;
                tvw.BeginUpdate();
                // create root node
                TreeNode node = tvw.Nodes.Add(ROOT_NAME);
                // add subdirs - this is a recursive function and is re-called
                // for every directory found until all have been scanned
                AddDirs(node);
                tvw.EndUpdate();
                // expand root
                node.Expand();
                // change cursor back to normal
                Cursor.Current = Cursors.Default;
            }
            return base.ShowDialog();
        }
        // since we have a fictitios root we need to override the default
        // fullpath function to return a legitimate path
        String FullPath(TreeNode node)
        {
            return (node.Text == ROOT_NAME) ? "\\" : node.FullPath.Substring(ROOT_NAME.Length);
        }
        // recursive function that reads all the subdirectories of a given
        // directory and adds them to the treeview. the node parameter is
        // the directory/node to be scanned
        private void AddDirs(TreeNode node)
        {
            // holds the directories we find
            String[] dirs = new string[0];
            // sub-node
            TreeNode sNode = null;
            // get subdirs
            try
            {
                dirs = Directory.GetDirectories(FullPath(node));
            }
            catch { }
            // sort them
            Array.Sort(dirs);
            foreach (String dir in dirs)
            {
                // use the file name of the path as treenode name
                sNode = node.Nodes.Add(new FileInfo(dir).Name);
                // image - directory
                sNode.ImageIndex = 0;
                sNode.SelectedImageIndex = 1;
                // go do it now for the newly found dir
                AddDirs(sNode);
            }
        }
        // when a treenode is selected - we display the media files in it
        // in the listview
        private void tvw_AfterSelect(object sender, TreeViewEventArgs e)
        {
            Cursor.Current = Cursors.WaitCursor;
            lvw.BeginUpdate();
            // clear all previous files
            lvw.Items.Clear();
            // clear result set
            BookFiles.Clear();
            // if a treenode is selected - go fetch the files
            if(e.Node != null)
                if (e.Node.IsSelected) 
                    ShowFiles(FullPath(e.Node));
            // show file count 
            spl.Refresh();
            lvw.EndUpdate();
            Cursor.Current = Cursors.Default;
        }
        // scan a directory (path) find media files and add to listview
        // this is a recursive function that may be called for all
        // subdirectories if relevant chekbox is checked
        private void ShowFiles(String path)
        {
            // get files
            String[] files = GetMediaFiles(path);
            // sort
            Array.Sort(files);
            foreach (String file in files)
            {
                // extract file name from path
                // add to listview
                ListViewItem item = lvw.Items.Add(new ListViewItem(new FileInfo(file).Name));
                // set image index
                item.ImageIndex = 2;
                // default state is checked (included)
                item.Checked = true;
                // add files to result set
                BookFiles.Add(file); 
            }
            // subdirs are to scanned:
            if (chkRec.Checked)
            {
                // get subdirs
                String[] dirs = Directory.GetDirectories(path);
                // sort
                Array.Sort(dirs);
                // repeat scan for all found subdirs
                foreach (String dir in dirs)
                    ShowFiles(dir);
            }
        }

        public String[] GetMediaFiles(String path)
        {
            // audio files supported by WMP
            String[] MEDIA_FILES = {"*.mp3", "*.wav", "*.snd", "*.wma", "*.mid"};
            ArrayList files = new ArrayList();
            foreach (String pattern in MEDIA_FILES)
            {
                try
                {
                    files.AddRange(Directory.GetFiles(path, pattern));
                }
                catch (Exception e)
                {
                    MessageBox.Show("File System Error : " + e.Message);
                }
            }
            return (String[])files.ToArray(typeof(String));
        }

        // use splitter as a paint area to display file count
        private void spl_Paint(object sender, PaintEventArgs e)
        {
            // erase the whole control face with its backcolor
            e.Graphics.FillRectangle(new SolidBrush(spl.BackColor), 0, 0,
                spl.Width, spl.Height);
            // draw rectangle around it
            e.Graphics.DrawRectangle(new Pen(Color.Silver, 1),
                new Rectangle(0, 0, spl.Width - 2, spl.Height - 2));
            // if no files are displayed - we are done
            if (lvw.Items.Count <= 0) return;
            // set display string
            String txt = lvw.Items.Count.ToString() + " Files";
            // get string sizes
            SizeF strWH = e.Graphics.MeasureString(txt, this.Font);
            // display string in mid horizontal and vertical point
            e.Graphics.DrawString(txt, this.Font, new SolidBrush(Color.White),
                (spl.Width / 2 - strWH.Width / 2),
                (spl.Height / 2 - strWH.Height / 2));
        }
        // user hit OK
        private void btnOK_Click(object sender, EventArgs e)
        {
            FlashControl((Control)sender);
            // only if a directory is selected
            if (tvw.SelectedNode != null)
            {
                // bookfiles already holds all files, however, user might have
                // deselected some/all
                // remove deselected files from result set
                bool found = false;
                for (int i = 0; i < lvw.Items.Count; i++)
                {
                    if (lvw.Items[i].Checked)
                    {
                        found = true;
                        break;
                    }
                }
                if (!found)
                    return;
                for (int i = lvw.Items.Count - 1; i >= 0; i--)
                {
                    if (!lvw.Items[i].Checked)
                        BookFiles.RemoveAt(i);
                }
                // directory name is default book name
                DefaultBookName = tvw.SelectedNode.Text;
                // go back
                DialogResult = DialogResult.OK;
            }
        }
        // user hit cancel
        private void btnCancel_Click(object sender, EventArgs e)
        {
            FlashControl((Control)sender);
            // reset result set
            DefaultBookName = "";
            BookFiles.Clear();
            // go back
            DialogResult = DialogResult.Cancel;
        }
        // draw pic pitton if skin load failed
        public void Pic_Paint(object sender, PaintEventArgs e)
        {
            PictureBox obj = (PictureBox)sender;
            if (obj.Image == null)
            {
                String str = (String)obj.Tag;
                e.Graphics.FillRectangle(new SolidBrush(Color.White),
                    1, 1, obj.Width - 2, obj.Height - 2);
                if (str.Length > 0)
                {
                    float size = Font.Size + 1;
                    Font font;
                    SizeF strWH;
                    do
                    {
                        size--;
                        font = new Font(Font.Name, size, FontStyle.Bold);
                        strWH = e.Graphics.MeasureString(str, font);
                    } while (strWH.Width > obj.Width);
                    e.Graphics.DrawString(str, font, new SolidBrush(Color.Black),
                        (obj.Width - strWH.Width) / 2,
                        (obj.Height - strWH.Height) / 2);
                }
            }
        }
        // function used by the frmPlayer and this form to provide visual 
        // confirmation that a button (actually a picture box) was pressed:
        public void FlashControl(Control Wnd)
        {
            // create a graphics object from the control's dc
            IntPtr hDC = GetDC(Wnd.Handle);
            Graphics dc = Graphics.FromHdc(hDC);
            // paint the whole control area black
            dc.FillRectangle(new SolidBrush(Wnd.BackColor), 0, 0,
                Wnd.Width, Wnd.Height);
            // allow effect to take place
            Application.DoEvents();
            // go sleep for a while (60 milliseconds)
            Thread.Sleep(60);
            // release resources
            ReleaseDC(Wnd.Handle, hDC);
            dc.Dispose();
            // have the control re-paint itself
            Wnd.Refresh();
        }

        private void chkRec_CheckStateChanged(object sender, EventArgs e)
        {
            tvw_AfterSelect(tvw, new TreeViewEventArgs(tvw.SelectedNode, TreeViewAction.Unknown));
        }

        private void picNone_Click(object sender, EventArgs e)
        {
            CheckItems(sender, false);
        }

        private void picAll_Click(object sender, EventArgs e)
        {
            CheckItems(sender, true);
        }

        private void CheckItems(object sender, bool Value)
        {
            FlashControl((Control)sender);
            foreach (ListViewItem item in lvw.Items)
                item.Checked = Value;
        }
    }
}