Update DownloadThread.cs

winform1/DownloadThread.cs

-using System;
+using System;
 using System.IO;
 using System.Net;
-
+using System.Security.Cryptography;
+using System.Text;
 
 namespace winform1
 {
     class DownloadThread
     {
-        /// <summary>
-        /// 线程开始事件
-        /// </summary>
-        public event EventHandler threadStartEvent;
-        /// <summary>
-        /// 线程执行时事件
-        /// </summary>
-        public event EventHandler threadEvent;
-        /// <summary>
-        /// 线程结束事件
-        /// </summary>
-        public event EventHandler threadEndEvent;
+        public delegate void EventDownloadStart(long totalSize);
+        public delegate void EventDownloadIng(long curDownloadSize);
+        public delegate void EventCheckingMd5();
+        public delegate void EventDownloadDone();
+
+        public event EventDownloadStart eventDownloadStart;
+        public event EventDownloadIng eventDownloadIng;
+        public event EventCheckingMd5 eventCheckingMd5;
+        public event EventDownloadDone eventDownloadDone;
+
+        public static string GetMD5FromFile(string filename)
+        {
+            try
+            {
+                FileStream fs = new FileStream(filename, FileMode.Open);
+                MD5CryptoServiceProvider md5Helper = new MD5CryptoServiceProvider();
+                byte[] data = md5Helper.ComputeHash(fs);
+                fs.Close();
+                StringBuilder sbr = new StringBuilder();
+                for (int i = 0; i < data.Length; ++i)
+                {
+                    sbr.Append(data[i].ToString("X2"));
+                }
+                string md5Str = sbr.ToString();
+                return md5Str;
+            }
+            catch (Exception)
+            {
+                throw;
+            }
+        }
 
         /// <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>     
-        public void RunMethod(string url, string filename)
+        public void RunMethod(string url, string filename, long totalSize, string md5)
         {
             try
             {
+                Stream st;
+                Stream so;
+
                 HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
-                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
+                request.Timeout = 10000;
+
                 //通知主界面,我开始了, response.ContentLength用来设置进度条的最大值
-                threadStartEvent.Invoke(response.ContentLength, null);
+                eventDownloadStart(totalSize);
+
+                if (File.Exists(filename))
+                {
+                    //续传
+                    so = File.OpenWrite(filename);
+                    if (so.Length < totalSize)
+                    {
+                        so.Seek(so.Length, SeekOrigin.Current);
+                        request.AddRange((int)so.Length);
+                    }
+                    else
+                    {
+                        so.Close();
+                        so = new FileStream(filename, FileMode.Create);
+                    }
+
+                }
+                else
+                {
+                    so = new FileStream(filename, FileMode.Create);
+                }
+
+                long totalDownloadedByte = so.Length;
+                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
+
+                st = response.GetResponseStream();
 
-                Stream st = response.GetResponseStream();
-                Stream so = new FileStream(filename, FileMode.Create);
-                long totalDownloadedByte = 0;
                 byte[] by = new byte[1024];
                 int osize = st.Read(by, 0, by.Length);
                 while (osize > 0)
@@ -46,13 +93,22 @@ namespace winform1
                     osize = st.Read(by, 0, by.Length);
 
                     //通知主界面我正在执行,totalDownloadedByte表示进度条当前进度
-                    threadEvent.Invoke(totalDownloadedByte, null);
+                    eventDownloadIng(totalDownloadedByte);
                 }
                 so.Close();
                 st.Close();
 
-                //通知主界面我已经完成了
-                threadEndEvent.Invoke(null, null);
+                eventCheckingMd5();
+                if (GetMD5FromFile(filename) != md5)
+                {
+                    //md5校验不通过，重新传
+                    RunMethod(url, filename, totalSize, md5);
+                }
+                else
+                {
+                    //通知主界面我已经完成了
+                    eventDownloadDone();
+                }
             }
             catch (Exception)
             {