C#下载http文件

@(编程)

using System;
using System.IO;
using System.Net;

namespace Wisdombud.Util
{
    public class HttpHelper
    {
        public static bool DownloadFile(string localFile, string webFile)
        {
            bool flag = false;
            long SPosition = 0;
            FileStream FStream;
            if (File.Exists(localFile))
            {
                File.Delete(localFile);
                FStream = File.OpenWrite(localFile);
                SPosition = FStream.Length;
                FStream.Seek(SPosition, SeekOrigin.Current);
            }
            else
            {
                FStream = new FileStream(localFile, FileMode.Create);
                SPosition = 0;
            }
            try
            {
                HttpWebRequest myRequest = (HttpWebRequest)HttpWebRequest.Create(webFile);
                if (SPosition > 0)
                    myRequest.AddRange((int)SPosition);
                Stream myStream = myRequest.GetResponse().GetResponseStream();
                byte[] btContent = new byte[512];
                int intSize = 0;
                intSize = myStream.Read(btContent, 0, 512);
                while (intSize > 0)
                {
                    FStream.Write(btContent, 0, intSize);
                    intSize = myStream.Read(btContent, 0, 512);
                }
                FStream.Close();
                myStream.Close();
                flag = true;
            }
            catch (Exception)
            {
                FStream.Close();
                flag = false;
            }
            return flag;
        }
    }
}