拖放操作和文件复制小功能

一直都没试过拖放操作的用处，今天试了试，发现真的很好用！！
下面的代码没有打入注释，加入了一个ListBox，当文件拖放上来后，讲内容显示在里面
private void lstFilePath_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                e.Effect = DragDropEffects.Link;
            }
            else
            {
                e.Effect = DragDropEffects.None;
            }
        }

        private void lstFilePath_DragDrop(object sender, DragEventArgs e)
        {
            foreach (string strPath in (string[])e.Data.GetData(DataFormats.FileDrop))
            {
                lstFilePath.Items.Add(strPath);
            }
        }
将整个窗体代码都复制下来，是一个复制的小程序，将拖放到LISTBOX里的文件复制到文本框里指定的位置,里面用到了一个外部控件，可以使用普通的button替换之

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.Diagnostics;

namespace PersonalDisk
{
    public partial class frmDrag : Form
    {
        /**//// <summary>
        /// 获得/设置一个值，判断是否已经存在了一个类的实例
        /// </summary>
        public static bool IsExist=false;
        
        public frmDrag()
        {
            InitializeComponent();
            frmDrag.IsExist = true;
        }

        private void frmDrag_MouseDown(object sender, MouseEventArgs e)
        {
            //如果鼠标指针在标题栏范围内并且按下了鼠标左键，则触发移动标题栏方法
            if (e.Button == MouseButtons.Left && e.Y <= 25)
            {
                Program.ReleaseCapture();
                Program.SendMessage(this.Handle, Program.WM_SYSCOMMAND, Program.SC_MOVE + Program.HTCAPTION, 0);
            }
        }

        private void picControlClose_Click(object sender, EventArgs e)
        {
            frmDrag.IsExist = false;            
            this.Close();
        }

        private void picControlMin_Click(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Minimized;
        }

        private void lstFilePath_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                e.Effect = DragDropEffects.Link;
            }
            else
            {
                e.Effect = DragDropEffects.None;
            }
        }

        private void lstFilePath_DragDrop(object sender, DragEventArgs e)
        {
            foreach (string strPath in (string[])e.Data.GetData(DataFormats.FileDrop))
            {
                lstFilePath.Items.Add(strPath);
            }
        }

        private void ExBtnClose_ClickEvent(object sender, EventArgs e)
        {
            picControlClose_Click(null,null);
        }

        private void ExBtnClear_ClickEvent(object sender, EventArgs e)
        {
            lstFilePath.Items.Clear();
        }

        private void ExBtnDel_ClickEvent(object sender, EventArgs e)
        {
            lstFilePath.Items.RemoveAt(lstFilePath.SelectedIndex);
        }

        private void picControlBring_Click(object sender, EventArgs e)
        {
            if (this.TopMost == true)
            {
                this.TopMost = false;
                picControlBring.Image = PersonalDisk.Properties.Resources.btnBottom;
            }
            else
            {
                this.TopMost = true;
                picControlBring.Image = PersonalDisk.Properties.Resources.btnTop;
            }
        }

        private void ExBtnExecute_ClickEvent(object sender, EventArgs e)
        {
            ExBtnExecute.CtlEnabled = false;

            for (int i = 0; i < lstFilePath.Items.Count; i++)
            {
                Application.DoEvents();
                lstFilePath.SetSelected(i, true);
                
                //如果当前字符串是一个目录则.
                if (Directory.Exists(lstFilePath.Items[i].ToString()))
                {
                    CopyDirectory(lstFilePath.Items[i].ToString(), txtSelDrive.Text +"\\"+ Path.GetFileName(lstFilePath.Items[i].ToString()));
                    lstFilePath.Items[i] = "复制完成";
                }
                else
                {
                    if (!File.Exists(lstFilePath.Items[i].ToString())) continue; //如果文件不存在继续下一个循环
                    File.Copy(lstFilePath.Items[i].ToString(), txtSelDrive.Text + "\\" + Path.GetFileName(lstFilePath.Items[i].ToString()));
                    lstFilePath.Items[i] = "复制完成";
                }
            }

            lstFilePath.Items.Clear();
            ExBtnExecute.CtlEnabled = true;
        }

        private void txtSelDrive_DoubleClick(object sender, EventArgs e)
        {
            FolderSelDialog.ShowDialog(this);
            txtSelDrive.Text = FolderSelDialog.SelectedPath;
        }
        
        /**//// <summary>
        /// 复制一个目录下的所有文件或目录到一个新的目录下
        /// </summary>
        /// <param name="sourcePath">源目录路径</param>
        /// <param name="destPath">目标目录路径</param>
        private void CopyDirectory(string sourcePath, string destPath)
        {
            try
            {
                //如果目标路径没有以\结尾则加之
                if (destPath[destPath.Length - 1] != Path.DirectorySeparatorChar)
                {
                    destPath += Path.DirectorySeparatorChar;
                }
                if (!Directory.Exists(destPath))
                {
                    Directory.CreateDirectory(destPath);
                }
                string[] fileList = Directory.GetFileSystemEntries(sourcePath);
                foreach (string file in fileList)
                {
                    //如果是一个目录则
                    if (Directory.Exists(file))
                    {
                        CopyDirectory(file, destPath + Path.GetFileName(file));
                    }
                    else
                    {
                        File.Copy(file, destPath + Path.GetFileName(file),true);
                    }
                }
            }
            catch(IOException ioe)
            {
                MessageBox.Show(ioe.Message, "复制文件时出错", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
        }
    }
}