winfrom下载文件进度条

最新推荐文章于 2023-06-25 16:21:11 发布

wanglei_samrtfish

最新推荐文章于 2023-06-25 16:21:11 发布

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分类专栏： asp.net

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本文介绍如何在C#的WinForm应用程序中实现文件下载，并同时展示下载进度条。通过创建一个简单的用户界面，点击按钮启动下载，进度条实时更新下载进度，当下载完成后显示提示消息。

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1.后台代码

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

namespace WindowsFormsApplication1
{
    public partial class Downfiles : Form
    {
        public Downfiles()
        {
            InitializeComponent();
        }

        private void btndown_Click(object sender, EventArgs e)
        {
            DownloadFile("http://localhost:3818/Images/力软Doc.rar", @"D:\20190107_力软Doc.rar", progressBar1, label1);
        }

        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
                    if (percent == 100) {
                        MessageBox.Show("下载完毕");
                    }

                }
                so.Close();
                st.Close();
            }
            catch (System.Exception)
            {
                throw;
            }
        }
    }
}

2.界面设计