C#使用HttpWebRequest下载文件

添加引用

using System.IO;
using System.Web;
using System.Net;
using System.Threading;
using System.Windows.Forms;

        public static bool HttpDownload(string url)
        {
            try
            {
                string fileName = Path.GetFileName(url);
                string filePath = Application.StartupPath + "\\" + fileName;
                if (File.Exists(filePath))
                {
                    File.Delete(filePath);
                }
                FileStream fs = new FileStream(filePath, FileMode.Append, FileAccess.Write, FileShare.ReadWrite);
                // 设置参数
                HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
                //发送请求并获取相应回应数据
                HttpWebResponse response = request.GetResponse() as HttpWebResponse;
                //直到request.GetResponse()程序才开始向目标网页发送Post请求
                Stream responseStream = response.GetResponseStream();
                //创建本地文件写入流
                byte[] bArr = new byte[1024];
                int iTotalSize = 0;
                int size = responseStream.Read(bArr, 0, (int)bArr.Length);
                while (size > 0)
                {
                    iTotalSize += size;
                    fs.Write(bArr, 0, size);
                    size = responseStream.Read(bArr, 0, (int)bArr.Length);
                }
                fs.Close();
                responseStream.Close();
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }