Form1.cs

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


namespace Wallpapers
{

    public partial class Form1 : Form
    {

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]         // подключение .dll библиотек для работы с рабочим столом 
        private static extern int SystemParametersInfo(UInt32 uAction, UInt32 uParam, String lpvParam, UInt32 fuWinIni);
        public const int SPI_SETDESKWALLPAPER = 20;
        public const int SPIF_UPDATEINIFILE = 1;
        public const int SPIF_SENDCHANGE = 2;
        private string fullPath;

        
        public Form1()
        {
            InitializeComponent();
            DriveTreeInit(); //инициализация дерева папок с помощью метода DriveTreeInit
        }


        private void toolStripButton2_Click(object sender, EventArgs e)
        {

        }


        public void DriveTreeInit()  //Метод инициализации дерева папок
        {
            string[] drivesArray = Directory.GetLogicalDrives();

            treeView1.BeginUpdate();
            treeView1.Nodes.Clear();

            foreach(string s in drivesArray)
            {
                TreeNode drive = new TreeNode(s, 0, 0);
                treeView1.Nodes.Add(drive);
                GetDirs(drive);
            } 

            treeView1.EndUpdate();
        }


        public void GetDirs(TreeNode node) //метод добавляет в список содержимое крневого каталога
        {
            DirectoryInfo[] diArray;
            node.Nodes.Clear();
            string fullPath = node.FullPath;
            DirectoryInfo di = new DirectoryInfo(fullPath);

            try { diArray = di.GetDirectories(); }
            catch { return; }

            foreach (DirectoryInfo dirinfo in diArray)
            {
                TreeNode dir = new TreeNode(dirinfo.Name, 1, 2);
                node.Nodes.Add(dir);
            }
        }

        private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
        {
            string[] drivesArray = Directory.GetLogicalDrives(); // используем статический метод Directory.GetLogicalDrives 
                                                                 // для получения списков логических элементов
            foreach (string s in drivesArray)
            Console.Write("{0} ", s);
            DirectoryInfo[] diArray;
            string fullPath = "C:\\";

            DirectoryInfo di = new DirectoryInfo(fullPath); // с помощью метода DirectoryInfo получаем список
                                                            //всех подкаталогов
            try{ diArray = di.GetDirectories(); }
            catch{ return; }
        }


        private void treeView1_OnBeforeExpand(object sender, System.Windows.Forms.TreeViewCancelEventArgs e)
        {
            treeView1.BeginUpdate();

            foreach (TreeNode node in e.Node.Nodes)
            {
                GetDirs(node);
            }

            treeView1.EndUpdate();
        }


        private void listView1_SelectedIndexChanged(object sender, System.Windows.Forms.TreeViewEventArgs e)
        {
            listView1.Items.Clear();
            ListViewItem lvi = new ListViewItem("myfile.txt");
            lvi.SubItems.Add("1024");
            lvi.SubItems.Add("10-05-2003");
            listView1.Items.Add(lvi);
        }

        private void treeView1_OnAfterSelect(object sender,System.Windows.Forms.TreeViewEventArgs e)
        {
            TreeNode selectedNode = e.Node;
            fullPath = selectedNode.FullPath;

            DirectoryInfo di = new DirectoryInfo(fullPath);
            FileInfo[] fiArray;
            DirectoryInfo[] diArray;

            try { fiArray = di.GetFiles(); diArray = di.GetDirectories(); }
            catch { return; }

            listView1.Items.Clear();

            foreach (DirectoryInfo dirInfo in diArray)
            {
                ListViewItem lvi = new ListViewItem(dirInfo.Name);
                lvi.SubItems.Add("0");
                lvi.SubItems.Add(dirInfo.LastWriteTime.ToString());
                lvi.ImageIndex = 0;

                listView1.Items.Add(lvi);
            }


            foreach (FileInfo fileInfo in fiArray)
            {
                ListViewItem lvi = new ListViewItem(fileInfo.Name);
                lvi.SubItems.Add(fileInfo.Length.ToString());
                lvi.SubItems.Add(fileInfo.LastWriteTime.ToString());

                string filenameExtension = Path.GetExtension(fileInfo.Name).ToLower();
                listView1.Items.Add(lvi);
            }
        }


        private void listView1_SelectedIndexChanged(object sender, EventArgs e)
        {

        }

       
        private void listView1_OnItemActivate(object sender, System.EventArgs e)
        {
            foreach(ListViewItem lvi in listView1.SelectedItems)
            {
                this.loadImage(lvi, pictureBox1);
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (listView1.SelectedIndices.Count > 0 )
            {
                int oldSelection = listView1.SelectedIndices[0];
                listView1.SelectedIndices.Clear();
                if (1 <= oldSelection)
                    if (oldSelection - 1 <= listView1.Items.Count)
                    {
                        listView1.SelectedIndices.Add(oldSelection - 1);
                    }
                else { listView1.SelectedIndices.Add(1); }
            }

            foreach (ListViewItem lvi in listView1.SelectedItems)
            {
                this.loadImage(lvi, pictureBox1);
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            if (listView1.SelectedIndices.Count > 0)
            {
                int oldSelection = listView1.SelectedIndices[0];
                listView1.SelectedIndices.Clear();
                if (oldSelection + 1 >= listView1.Items.Count) listView1.SelectedIndices.Add(0);
                else listView1.SelectedIndices.Add(oldSelection + 1);
            }

            foreach (ListViewItem lvi in listView1.SelectedItems)
            {
                this.loadImage(lvi, pictureBox1);
            }
        }

        
        private void toolStripButton6_Click(object sender, EventArgs e)
        {
            string path = pictureBox1.ImageLocation;
            System.Drawing.Image image = System.Drawing.Image.FromFile(path); ;
            image.Save(@"C:\WINDOWS\Web\Wallpaper\test.bmp", System.Drawing.Imaging.ImageFormat.Bmp);
            SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, @"C:\WINDOWS\Web\Wallpaper\test.bmp", SPIF_UPDATEINIFILE | SPIF_SENDCHANGE);
        }

        private void оПрограммеToolStripMenuItem1_Click(object sender, EventArgs e)
        {
            MessageBox.Show("Программа для оформления рабочего стола\n\n\n Лось Татьяна, 2014г.", "Wall Changer 1.0");
        }


        private void снимокЭкранаToolStripMenuItem1_Click(object sender, EventArgs e)
        {
            var boom = Screen.GetBounds(new Point(0, 0));
            var bmp = new Bitmap(boom.Width, boom.Height);
            using (var g = Graphics.FromImage(bmp))
                g.CopyFromScreen(0, 0, 0, 0, bmp.Size);
            bmp.Save(@"C:\Documents and Settings\User\Мои документы\Мои рисунки\screen.bmp");

        }


        private void Form1_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.S) снимокЭкранаToolStripMenuItem1_Click(sender, e);  
        }

       
        private void toolStripButton10_Click(object sender, EventArgs e)       
        {

            Timer timer = new Timer();
            timer.Interval = 1200000;
            timer.Tick += button3_Click;
            timer.Start();
        }

        private void pictureBox1_Click(object sender, EventArgs e)
        {

        }

        private void folderBrowserDialog1_HelpRequest(object sender, EventArgs e)
        {
      
        }

        private void button3_Click(object sender, EventArgs e)
        {
            if (listView1.SelectedIndices.Count > 0)
            {
                int oldSelection = listView1.SelectedIndices[0];
                listView1.SelectedIndices.Clear();
                if (oldSelection + 1 >= listView1.Items.Count) listView1.SelectedIndices.Add(0);
                else listView1.SelectedIndices.Add(oldSelection + 1);
            }

            foreach (ListViewItem lvi in listView1.SelectedItems)
            {
                this.loadImage(lvi, pictureBox2);
            }
            string path = pictureBox2.ImageLocation;
            System.Drawing.Image image = System.Drawing.Image.FromFile(path); ;
            image.Save(@"C:\WINDOWS\Web\Wallpaper\test.bmp", System.Drawing.Imaging.ImageFormat.Bmp);
            SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, @"C:\WINDOWS\Web\Wallpaper\test.bmp", SPIF_UPDATEINIFILE | SPIF_SENDCHANGE);
        }

        private void loadImage(ListViewItem lvi, PictureBox pictureBox) {
            string ext = Path.GetExtension(lvi.Text).ToLower();
            if (ext == ".jpg" || ext == ".jpeg" || ext == ".bmp" || ext == ".png")
            {
                try { pictureBox.Load(Path.Combine(fullPath, lvi.Text)); }
                catch { return; }
            }
        }

        private void pictureBox2_Click(object sender, EventArgs e)
        {

        }

        private void Form1_Resize(object sender, EventArgs e)
        {
            if (WindowState == FormWindowState.Minimized) 
            Hide();
            notifyIcon1.BalloonTipTitle = "Программа была спрятана";
            notifyIcon1.BalloonTipText = "Обратите внимание что программа была спрятана в трей и продолжит свою работу.";
            notifyIcon1.ShowBalloonTip(5000); // Параметром указываем количество миллисекунд, которое будет показываться подсказка
        }

        private void notifyIcon1_MouseDoubleClick(object sender, MouseEventArgs e)
        {
            Show();
            WindowState = FormWindowState.Normal;
        }

        private void menuStrip1_ItemClicked(object sender, ToolStripItemClickedEventArgs e)
        {

        }

        private void listView1_SelectedIndexChanged_1(object sender, EventArgs e)
        {

        }
        

       
    }
}