C#异步批量下载文件
实现原理：采用WebClient进行批量下载任务，简单的模拟迅雷下载效果！
废话不多说,先看掩饰效果：
具体实现步骤如下：
1.新建项目：WinBatchDownload
2.先建一个Windows窗体：FrmBatchDownload,加载事件FrmBatchDownload_Load
3.放置一个Button按钮：btnStartDownLoad,单机事件btnStartDownLoad_Click
4.放置一个DataGridView：dgvDownLoad.
5.具体代码如下：
using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Text;using System.Windows.Forms;#region 命名空间using System.Threading;using System.Runtime.InteropServices;using System.Net;#endregionnamespace WinBatchDownload{ public partial class FrmBatchDownload : Form { #region 全局成员 //存放下载列表 List<SynFileInfo> m_SynFileInfoList; #endregion #region 构造函数 public FrmBatchDownload() { InitializeComponent(); m_SynFileInfoList = new List<SynFileInfo>(); } #endregion #region 窗体加载事件 private void FrmBatchDownload_Load(object sender, EventArgs e) { //初始化DataGridView相关属性 InitDataGridView(dgvDownLoad); //添加DataGridView相关列信息 AddGridViewColumns(dgvDownLoad); //新建任务 AddBatchDownload(); } #endregion #region 添加GridView列 /// <summary> /// 正在同步列表 /// </summary> void AddGridViewColumns(DataGridView dgv) { dgv.Columns.Add(new DataGridViewTextBoxColumn() { DataPropertyName = "DocID", HeaderText = "文件ID", Visible = false, Name = "DocID" }); dgv.Columns.Add(new DataGridViewTextBoxColumn() { AutoSizeMode = DataGridViewAutoSizeColumnMode.None, DataPropertyName = "DocName", HeaderText = "文件名", Name = "DocName", Width = 300 }); dgv.Columns.Add(new DataGridViewTextBoxColumn() { DataPropertyName = "FileSize", HeaderText = "大小", Name = "FileSize", }); dgv.Columns.Add(new DataGridViewTextBoxColumn() { DataPropertyName = "SynSpeed", HeaderText = "速度", Name = "SynSpeed" }); dgv.Columns.Add(new DataGridViewTextBoxColumn() { DataPropertyName = "SynProgress", HeaderText = "进度", Name = "SynProgress" }); dgv.Columns.Add(new DataGridViewTextBoxColumn() { DataPropertyName = "DownPath", HeaderText = "下载地址", Visible = false, Name = "DownPath" }); dgv.Columns.Add(new DataGridViewTextBoxColumn() { DataPropertyName = "SavePath", HeaderText = "保存地址", Visible = false, Name = "SavePath" }); dgv.Columns.Add(new DataGridViewTextBoxColumn() { DataPropertyName = "Async", HeaderText = "是否异步", Visible = false, Name = "Async" }); } #endregion #region 添加下载任务并显示到列表中 void AddBatchDownload() { //清空行数据 dgvDownLoad.Rows.Clear(); //添加列表(建立多个任务) dgvDownLoad.Rows.Add(new object[]{ "0",//文件id "PPTV客户端.exe",//文件名称 "21.2 MB",//文件大小 "0 KB/S",//下载速度 "0%",//下载进度 "http://download.pplive.com/pptvsetup_3.2.1.0076.exe",//远程服务器下载地址 "D:\\PPTV客户端.exe",//本地保存地址 true//是否异步 }); dgvDownLoad.Rows.Add(new object[]{ "1", "PPS客户端.exe", "14.3 MB", "0 KB/S", "0%", "http://download.ppstream.com/ppstreamsetup.exe", "D:\\PPS客户端.exe", true }); dgvDownLoad.Rows.Add(new object[]{ "2", "美图看看客户端.exe", "4.1 MB", "0 KB/S", "0%", "http://kankan.dl.meitu.com/V2/1029/KanKan_kk360Setup.exe", "D:\\美图看看客户端.exe", true }); //取出列表中的行信息保存列表集合(m_SynFileInfoList)中 foreach (DataGridViewRow dgvRow in dgvDownLoad.Rows) { m_SynFileInfoList.Add(new SynFileInfo() { DocID = dgvRow.Cells["DocID"].Value.ToString(), DocName = dgvRow.Cells["DocName"].Value.ToString(), FileSize = 0, SynSpeed = dgvRow.Cells["SynSpeed"].Value.ToString(), SynProgress = dgvRow.Cells["SynProgress"].Value.ToString(), DownPath = dgvRow.Cells["DownPath"].Value.ToString(), SavePath = dgvRow.Cells["SavePath"].Value.ToString(), Async = Convert.ToBoolean(dgvRow.Cells["Async"].Value), RowObject = dgvRow }); } } #endregion #region 开始下载按钮单机事件 private void btnStartDownLoad_Click(object sender, EventArgs e) { //判断网络连接是否正常 if (isConnected()) { //设置不可用 btnStartDownLoad.Enabled = false; //设置最大活动线程数以及可等待线程数 ThreadPool.SetMaxThreads(3, 3); //判断是否还存在任务 if (m_SynFileInfoList.Count <= 0) AddBatchDownload(); foreach (SynFileInfo m_SynFileInfo in m_SynFileInfoList) { //启动下载任务 StartDownLoad(m_SynFileInfo); } } else { MessageBox.Show("网络异常!"); } } #endregion #region 检查网络状态 //检测网络状态 [DllImport("wininet.dll")] extern static bool InternetGetConnectedState(out int connectionDescription, int reservedValue); /// <summary> /// 检测网络状态 /// </summary> bool isConnected() { int I = 0; bool state = InternetGetConnectedState(out I, 0); return state; } #endregion #region 使用WebClient下载文件 /// <summary> /// HTTP下载远程文件并保存本地的函数 /// </summary> void StartDownLoad(object o) { SynFileInfo m_SynFileInfo = (SynFileInfo)o; m_SynFileInfo.LastTime = DateTime.Now; //再次new 避免WebClient不能I/O并发 WebClient client = new WebClient(); if (m_SynFileInfo.Async) { //异步下载 client.DownloadProgressChanged += new DownloadProgressChangedEventHandler(client_DownloadProgressChanged); client.DownloadFileCompleted += new AsyncCompletedEventHandler(client_DownloadFileCompleted); client.DownloadFileAsync(new Uri(m_SynFileInfo.DownPath), m_SynFileInfo.SavePath, m_SynFileInfo); } else client.DownloadFile(new Uri(m_SynFileInfo.DownPath), m_SynFileInfo.SavePath); } /// <summary> /// 下载进度条 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> void client_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e) { SynFileInfo m_SynFileInfo = (SynFileInfo)e.UserState; m_SynFileInfo.SynProgress = e.ProgressPercentage + "%"; double secondCount = (DateTime.Now - m_SynFileInfo.LastTime).TotalSeconds; m_SynFileInfo.SynSpeed = FileOperate.GetAutoSizeString(Convert.ToDouble(e.BytesReceived / secondCount), 2) + "/s"; //更新DataGridView中相应数据显示下载进度 m_SynFileInfo.RowObject.Cells["SynProgress"].Value = m_SynFileInfo.SynProgress; //更新DataGridView中相应数据显示下载速度(总进度的平均速度) m_SynFileInfo.RowObject.Cells["SynSpeed"].Value = m_SynFileInfo.SynSpeed; } /// <summary> /// 下载完成调用 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> void client_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e) { //到此则一个文件下载完毕 SynFileInfo m_SynFileInfo = (SynFileInfo)e.UserState; m_SynFileInfoList.Remove(m_SynFileInfo); if (m_SynFileInfoList.Count <= 0) { //此时所有文件下载完毕 btnStartDownLoad.Enabled = true; } } #endregion #region 需要下载文件实体类 class SynFileInfo { public string DocID { get; set; } public string DocName { get; set; } public int FileSize { get; set; } public string SynSpeed { get; set; } public string SynProgress { get; set; } public string DownPath { get; set; } public string SavePath { get; set; } public DataGridViewRow RowObject { get; set; } public bool Async { get; set; } public DateTime LastTime { get; set; } } #endregion #region 初始化GridView void InitDataGridView(DataGridView dgv) { dgv.AutoGenerateColumns = false;//是否自动创建列 dgv.AllowUserToAddRows = false;//是否允许添加行(默认：true) dgv.AllowUserToDeleteRows = false;//是否允许删除行(默认：true) dgv.AllowUserToResizeColumns = false;//是否允许调整大小(默认：true) dgv.AllowUserToResizeRows = false;//是否允许调整行大小(默认：true) dgv.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill;//列宽模式(当前填充)(默认：DataGridViewAutoSizeColumnsMode.None) dgv.BackgroundColor = System.Drawing.Color.White;//背景色(默认：ControlDark) dgv.BorderStyle = BorderStyle.Fixed3D;//边框样式(默认：BorderStyle.FixedSingle) dgv.CellBorderStyle = DataGridViewCellBorderStyle.SingleHorizontal;//单元格边框样式(默认：DataGridViewCellBorderStyle.Single) dgv.ColumnHeadersBorderStyle = DataGridViewHeaderBorderStyle.None;//列表头样式(默认：DataGridViewHeaderBorderStyle.Single) dgv.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.DisableResizing;//是否允许调整列大小(默认：DataGridViewColumnHeadersHeightSizeMode.EnableResizing) dgv.ColumnHeadersHeight = 30;//列表头高度(默认：20) dgv.MultiSelect = false;//是否支持多选(默认：true) dgv.ReadOnly = true;//是否只读(默认：false) dgv.RowHeadersVisible = false;//行头是否显示(默认：true) dgv.SelectionMode = DataGridViewSelectionMode.FullRowSelect;//选择模式(默认：DataGridViewSelectionMode.CellSelect) } #endregion #region 文件相关操作类分 /// <summary> /// 文件有关的操作类 /// </summary> public class FileOperate { #region 相应单位转换常量 private const double KBCount = 1024; private const double MBCount = KBCount * 1024; private const double GBCount = MBCount * 1024; private const double TBCount = GBCount * 1024; #endregion #region 获取适应大小 /// <summary> /// 得到适应大小 /// </summary> /// <param name="size">字节大小</param> /// <param name="roundCount">保留小数(位)</param> /// <returns></returns> public static string GetAutoSizeString(double size, int roundCount) { if (KBCount > size) return Math.Round(size, roundCount) + "B"; else if (MBCount > size) return Math.Round(size / KBCount, roundCount) + "KB"; else if (GBCount > size) return Math.Round(size / MBCount, roundCount) + "MB"; else if (TBCount > size) return Math.Round(size / GBCount, roundCount) + "GB"; else return Math.Round(size / TBCount, roundCount) + "TB"; } #endregion } #endregion }}到此批量下载功能实现完毕,上面写的代码比较灵活,需要的朋友可以根据自己的项目修改相关内容。
最后附上源码：WinBatchDownload.zip
作者：曾庆雷出处：http://www.cnblogs.com/zengqinglei本页版权归作者和博客园所有，欢迎转载，但未经作者同意必须保留此段声明， 且在文章页面明显位置给出原文链接，否则保留追究法律责任的权利
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