Thread thd = null;
        string thisPath = "";
        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog op = new OpenFileDialog();
            if (op.ShowDialog() == DialogResult.OK)
            {
                thisPath = op.FileName;
                thd = new Thread(new ThreadStart(th));
                thd.Start();
            }
        }
        private void th()
        {
                FileStream fs = new FileStream(thisPath, FileMode.Open, FileAccess.Read);
                long length = fs.Length;
                FileStream newfs = new FileStream("C:\\aa.rar", FileMode.Create, FileAccess.Write);
                byte[] bytes = new byte[Convert.ToInt32(fs.Length)];
                progressBar1.Maximum = 100;
                progressBar1.Value = 0;
                int post = 0;
                long of = 0;
                while (post < length)
                {
                    int i = fs.Read(bytes, post, 1);
                    newfs.Write(bytes, post, 1);
                    if (post > 0)
                    {
                        of = fs.Length / post;
                        of = 100 - of + 1;
                        if (of > 0 )
                        {
                            progressBar1.Value = Convert.ToInt32(of);
                        }
                    }
                    post = post + 1;
                }

                newfs.Close();
                newfs.Dispose();
                fs.Close();
                fs.Dispose();
             
                MessageBox.Show("传输成功");
            
        }

这样的文件传输好吗？
每次只发送1个字节


还有一个问题，执行时滚动条一开始走的很快，到最后就慢了，当到100%还要等上一会才提示MessageBox.Show("传输成功");这是为什么？

为什么没人理我？


最后还是自己解决了。。。。。。

说说个人观点:
FileStream fs = new FileStream(thisPath, FileMode.Open, FileAccess.Read);
                long length = fs.Length;
                FileStream newfs = new FileStream("C:\\aa.rar", FileMode.Create, FileAccess.Write);
                byte[] bytes = new byte[Convert.ToInt32(fs.Length)];  //你这个数组也太大了吧!!
                progressBar1.Maximum = 100;
                progressBar1.Value = 0;
                int post = 0;
                long of = 0;
                while (post < length)
                {
                    int i = fs.Read(bytes, post, 1);  //每次你都读一个,
                    newfs.Write(bytes, post, 1);        // 每次你都写一个,
                    if (post > 0)
                    {
                        of = fs.Length / post;
                        of = 100 - of + 1;
                        if (of > 0 )
                        {
                            progressBar1.Value = Convert.ToInt32(of);
                        }
                    }
                    post = post + 1;
                }

                newfs.Close();
                newfs.Dispose(); //上有关闭,不必手动释放
                fs.Close();
                fs.Dispose();    //.....等上一会才提示MessageBox.Show("传输成功");这是为什么？
你已经定义这么大的一个数,为何每次只读一个,可以一次写入啊,文件大就会出错了!

支持3楼的！
写代码最好写上注释这样对你会很好！