C# .net实现下载，带进度条

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;

namespace WinShowDown

{

public partial class FrmMain : Form

{

public FrmMain()

{

InitializeComponent();

}

private void btnDown_Click(object sender, EventArgs e)

{

DownloadFile("http://localhost:1928/WebServer/downloader/123.rar", @"C:\123.rar", progressBar1, label1);

}

/// <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, System.Windows.Forms.ProgressBar prog, System.Windows.Forms.Label label1)

{

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 = "当前补丁下载进度" + 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; } } }}