c# winform下载文件并显示进度条(保存路径可选择另存为)

开发工具 VS2010

功能实现

填写下载地址URL，点击另存为按钮，打开另存为对话框，可以选择保存路径，点击下载按钮进行下载，下载过程显示下载百分比和进度条。

窗体

组件 label  TextBox  Button  progressBar  saveFileDialog

获取saveFileDialog1文件名和路径

Path.GetDirectoryName(saveFileDialog1.FileName) //获取文件名(不包括路径)
Path.GetFileName(saveFileDialog1.FileName);//获取文件路径

下载功能实现

        /// <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)
        {
            if (URL == "")
            {
                MessageBox.Show("URL为空","消息提示",MessageBoxButtons.OK,MessageBoxIcon.Information);
                return;
            }
            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("00.00") + "%";
                    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
                    //下载完成后，弹出提示对话框
                    if (percent == 100)
                    {
                        MessageBox.Show("下载完成", "消息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    }
                }
                so.Close();
                st.Close();
            }
            catch (System.Exception ee)
            {
                //throw;
                MessageBox.Show(ee.Message, "消息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }

效果

完整代码

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;

using System.IO;//需添加的IO引用

namespace downloadFilePro
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
       
        //打开另存为对话框
        private void btnSave_Click(object sender, EventArgs e)
        {
            saveFileDialog1.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*";
            if (saveFileDialog1.ShowDialog() == DialogResult.OK)
            {
                textBox2.Text = Path.GetDirectoryName(saveFileDialog1.FileName) + @"\" + Path.GetFileName(saveFileDialog1.FileName);//获取文件路径
            }
        }
        //下载按钮
        private void btnDown_Click(object sender, EventArgs e)
        {
            //textBox1存放URL地址，textBox2存放另存为路径
            DownloadFile(textBox1.Text, textBox2.Text, 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)
        {
            if (URL == "")
            {
                MessageBox.Show("URL为空","消息提示",MessageBoxButtons.OK,MessageBoxIcon.Information);
                return;
            }
            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("00.00") + "%";
                    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
                    if (percent == 100)
                    {
                        MessageBox.Show("下载完成", "消息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    }
                }
                so.Close();
                st.Close();
            }
            catch (System.Exception ee)
            {
                //throw;
                MessageBox.Show(ee.Message, "消息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }
    }
}

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