using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
using System.Diagnostics;

namespace MyDownload
{
    public partial class MyDownload : Form
    {
        string Url = "";        //要下载的文件的地址
        string filePath = "";   //下载后文件保存地址
        //private const string applicationFile = "LMS";

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="Url"></param>
        /// <param name="filePath"></param>
        public MyDownload(string Url, string filePath)
        {
            InitializeComponent();
            this.label1.Text = "";
            this.Url = Url;
            this.filePath = filePath;
        }

        /// <summary>
        /// 清楚已有文件
        /// </summary>
        /// <param name="filepath"></param>
        private void RemoveSetupFile(string filepath)
        {
            try
            {
                string folder = new DirectoryInfo(filepath).FullName;
                //if (File.Exists(folder + @"\" + applicationFile + ".exe"))
                //{
                //    File.Delete(folder + @"\" + applicationFile + ".exe");
                //}
                //if (File.Exists(folder + @"\" + applicationFile + ".msi"))
                //{
                //    File.Delete(folder + @"\" + applicationFile + ".msi");
                //}
                if(File.Exists(folder))
                {
                    File.Delete(folder);
                }
            }
            catch { }
        }

        /// <summary>
        /// 下载
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnDown_Click(object sender, EventArgs e)
        {
            RemoveSetupFile(filePath);
            DownloadFile(Url, filePath);
            Process.Start(filePath);
            Application.Exit();
        }

        /// <summary>        
        /// c#,.net 下载文件        
        /// </summary>        
        /// <param name="URL">下载文件地址</param>
        /// <param name="Filename">下载后的存放地址</param>
        /// <param name="Prog">用于显示的进度条</param>
        public void DownloadFile(string URL, string filename)
        {
            float percent = 0;
            try
            {
                System.Net.HttpWebRequest Myrq = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(URL);
                System.Net.HttpWebResponse myrp = (System.Net.HttpWebResponse)Myrq.GetResponse();
                long totalBytes = myrp.ContentLength;
                if (prog != null)
                {
                    prog.Maximum = (int)totalBytes;
                }
                System.IO.Stream st = myrp.GetResponseStream();
                System.IO.Stream so = new System.IO.FileStream(filename, System.IO.FileMode.Create);
                long totalDownloadedByte = 0;
                byte[] by = new byte[1024];
                int osize = st.Read(by, 0, (int)by.Length);
                while (osize > 0)
                {
                    totalDownloadedByte = osize + totalDownloadedByte;
                    System.Windows.Forms.Application.DoEvents();
                    so.Write(by, 0, osize);
                    if (prog != null)
                    {
                        prog.Value = (int)totalDownloadedByte;
                    }
                    osize = st.Read(by, 0, (int)by.Length);

                    percent = (float)totalDownloadedByte / (float)totalBytes * 100;
                    label1.Text = "当前下载进度" + percent.ToString() + "%";
                    System.Windows.Forms.Application.DoEvents(); //必须加注这句代码，否则label1将因为循环执行太快而来不及显示信息
                }
                so.Close();
                st.Close();
            }
            catch (System.Exception)
            {
                throw;
            }
            this.Close();
        }

        /// <summary>
        /// 取消
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btn_Cancel_Click(object sender, EventArgs e)
        {
            Process.Start(filePath);
            Application.Exit();
        }
    }
}