文件复制

            FileStream fr = new FileStream(textBox1.Text, FileMode.Open, FileAccess.Read);

            FileInfo fi = new FileInfo(openFileDialog1.FileName);

            FileStream fw = new FileStream("f:\\"+fi.Name , FileMode.Create, FileAccess.Write);



            if (fr.CanRead)

            {

                long length = fr.Length;

                int size = 1024 * 1024;

                int count = (int)(length / size);

                int last = (int)(length % size);



                while (count > 0)

                {

                    byte[] buffer = new byte[size];

                    fr.Read(buffer, 0, buffer.Length);

                    fw.Write(buffer, 0, buffer.Length);

                    count--;

                }



                if (last > 0)

                {

                    byte[] buffer = new byte[last];

                    fr.Read(buffer, 0, buffer.Length);

                    fw.Write(buffer, 0, buffer.Length);

                }



                fr.Close();

                fw.Flush();

                fw.Close();

                MessageBox.Show("Done!");

            }