silverlight 文件下载若干方法

方法一：WebService

前台代码：

 <DataTemplate>
   <Button Content="下载" Height="23" Name="button3" Tag="{Binding Udocname}" Width="60" Click="button3_Click" />
</DataTemplate>
                             

后台代码：

        private void button3_Click(object sender, RoutedEventArgs e)
        {
            Button b = sender as Button;
            //实例化button

            //_file 要下载的文件路径
            //string _file = "http://localhost:8080/EHRWCF/upload/2.rar"; //这里改成你网站里的文件路径
            string _file = "http://192.168.1.102:8080/EHRWCF/upload/" + b.Tag.ToString();
            SaveFileDialog sf = new SaveFileDialog();
            sf.DefaultExt = "rar";
            sf.Filter = "rar压缩文件 (*.rar)|*.rar|zip压缩文件 (*.zip)|*.zip|所有文件 (*.*)|*.*";
            sf.FilterIndex = 1;
            if (sf.ShowDialog() != true) return;
            Stream clientStream = sf.OpenFile();
            Uri _uri = new Uri(_file, UriKind.Absolute);
            WebClient client = new WebClient();

            if (client.IsBusy)
            {
                client.CancelAsync();
            }
            client.OpenReadCompleted += new OpenReadCompletedEventHandler(client_OpenReadCompleted);

            client.OpenReadAsync(_uri, clientStream);
            
        }
        #region 异步文件下载
        void client_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
        {
            if (e.Error != null)
            {
                //txtinfo.Text += e.Error.Message;
                MessageBox.Show(e.Error.ToString());
                //MessageBox.Show("下载文件时出错，可能是文件已经不存在！");
                return;
            }
            if (e.Cancelled != true)
            {
                Stream clientStream = e.UserState as Stream;
                Stream serverStream = (Stream)e.Result;
                byte[] buffer = new byte[serverStream.Length];
                serverStream.Read(buffer, 0, buffer.Length);
                clientStream.Write(buffer, 0, buffer.Length);
                clientStream.Close();
                serverStream.Close();
            }
        }
        #endregion

方法2：使用下载控件类似于asp.net中的<a href="url"></a>方法

前台代码：

//引用命名空间
xmlns:localConv="clr-namespace:KX_EHR.Class"
<UserControl.Resources>
        <localConv:ConvtoAddStr x:Key="ConvtoAddString"/>
    </UserControl.Resources>

//datagrid中
<DataTemplate>
   <HyperlinkButton Content="下载" NavigateUri="{Binding Udocname,Converter={StaticResource ConvtoAddString}}"></HyperlinkButton>
</DataTemplate>

 后台类型转化器：

    /// <summary>
    /// 把代码转化成指定的类容
    /// </summary>
    /// <param name="value"></param>
    /// <param name="targetType"></param>
    /// <param name="parameter"></param>
    /// <param name="culture"></param>
    /// <returns></returns>
    public class ConvtoAddStr : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (!value.ToString().Contains(@"http://192.168.1.102:8080/EHRWCF/upload/"))
            {
                return @"http://192.168.1.102:8080/EHRWCF/upload/" + value;
            }
            else
                return value;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (value.ToString().Contains(@"http://192.168.1.102:8080/EHRWCF/upload/"))
            {
                return value.ToString().Replace(@"http://192.168.1.102:8080/EHRWCF/upload/", "");
            }
            else
                return value;
        }   
     }