Silverlight中用WCF实现文件快速上传(二、改进)

    上一篇中提到Silverlight + WCF实现文件上传的一个缺点：一次性的将文件读到内存。显然，当文件的尺寸大到内存难以容纳时，这种方法是有问题的。处理这个问题时，自然的会想到，可以边读边上传。实测的情况，该方法实现也很简单，下面简要描述一下。

    1. 创建解决方案的方法和修改配置的方法同“Silverlight中用WCF实现文件快速上传(一)”，不再赘述。

    2. Silverlight中的实现

    辅助类：

public class UserFile { public string Name { get; set; } //<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>名 public long Length { get; set; } //<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>长度 public int BytesRead { get; set; } //本次读到的字节数 public long BytesSent { get; set; } //已经发送（<a href="/tag/shangchuan/" target="_blank" class="keywords">上传</a>）的字节数 public Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.IO.FileStream FileStream { get; set; } //<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>流 } MainPage.cs中的实现： public partial class MainPage : UserControl { private const int BUFFER_SIZE = 2097152; //2MB private UserFile _file; private byte[] _buffer; private localService.Service1Client _client; public MainPage() { btnUploadFile.Click += new RoutedEventHandler(Button_Click); _buffer = new byte[BUFFER_SIZE]; _client = new localService.Service1Client(); //事件处理 _client.ActionUploadCompleted += new EventHandler<Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.ComponentModel.AsyncCompletedEventArgs>(_client_ActionUploadCompleted); } private void Button_Click(object sender,RoutedEventArgs e) { //选择本地<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>对话框 OpenFileDialog openFileDialog = new OpenFileDialog(); openFileDialog.Filter = "(*.*)|*.*"; //单选 openFileDialog.Multiselect = false; if (openFileDialog.ShowDialog() == true) { _file = new UserFile(); FileInfo fileInfo = openFileDialog.File; _file.Name = fileInfo.Name; _file.Length = fileInfo.Length; _file.BytesRead = 0; _file.BytesSent = 0; _file.FileStream = fileInfo.OpenRead(); //初始化进度条 prgUpload.Minimum = 0; prgUpload.Maximum = Math.Ceiling((double)_file.Length / (double)_buffer.Length); int bytesRead = _file.FileStream.Read(_buffer,_buffer.Length); if (bytesRead > 0) { _file.BytesRead = bytesRead; _client.ActionUploadAsync(_file.Name,_buffer,false); } else { _file.FileStream.Close(); } } } void _client_ActionUploadCompleted(object sender,Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.ComponentModel.AsyncCompletedEventArgs e) { if (e.Error == null) { _file.BytesSent += _file.BytesRead; prgUpload.Value = Math.Ceiling((double)_file.BytesSent / (double)_buffer.Length); //更新进度条 if (_file.BytesSent < _file.Length) { int bytesRead = _file.FileStream.Read(_buffer,_buffer.Length); if (bytesRead > 0) { _file.BytesRead = bytesRead; _client.ActionUploadAsync(_file.Name,true); } else { _file.FileStream.Close(); } } else { _file.FileStream.Close(); } } } } 

    3. 总结

    本方法实现了边读文件边上传，实测时可以快速上传任意大小的文件。另外，还增加了上传的进度条。