silverligth +wcf 下载文件

xaml：

<UserControl x:Class="FileSaveDialogDemo.MainPage" 

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"   

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 

    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"   

    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"   

    mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480">  

    <Canvas x:Name="LayoutRoot" Background="White">  

        <Button x:Name="btnSaveFile" Width="100" Height="20" 

                Content="Save File" Click="btnSaveFile_Click" 

                Canvas.Top="10" Canvas.Left="10"></Button> 

        <TextBlock x:Name="tblError" Canvas.Top="40" Canvas.Left="10"></TextBlock> 

    </Canvas> 

</UserControl> 

 

CS：

public partial class MainPage : UserControl  

    {

        #region Fields  

        private SaveFileDialog dialog;

        #endregion  

        #region Constructors  

        public MainPage()  

        {  

            InitializeComponent();  

            this.dialog = new SaveFileDialog();  

            try 

            {  

                this.dialog.DefaultExt = ".txt";  

                this.dialog.Filter = "Text Files|*.txt|Log Files|*.log|All Files|*.*";  

                this.dialog.FilterIndex = 2;  

            }  

            catch ( Exception ex )  

            {  

                this.tblError.Text = "Error configuring SaveFileDialog: " + ex.Message;  

            }  

        }

        #endregion  

        #region Handlers  

        private void btnSaveFile_Click( object sender, RoutedEventArgs e )  

        {  

            bool? dialogResult = this.dialog.ShowDialog();  

            if ( dialogResult == true )  

            {  

                try 

                {  

                    FilesServiceReference.FilesClient fileClient  

                        = new FilesClient();  

                    fileClient.GetFileCompleted  

                        += new EventHandler<GetFileCompletedEventArgs>(  

                            fileClient_GetFileCompleted );  

                    fileClient.GetFileAsync(“aa.xls”);  

                    this.tblError.Text = "Getting file from the server...";  

                }  

                catch ( Exception ex )  

                {  

                    this.tblError.Text = "Error calling service: " + ex.Message;  

                }  

            }  

        }  

        void fileClient_GetFileCompleted( object sender, GetFileCompletedEventArgs e )  

        {  

            try 

            {  

                byte[] fileBytes = e.Result as byte[];  

                using ( Stream fs = ( Stream )this.dialog.OpenFile() )  

                {  

                    fs.Write( fileBytes, 0, fileBytes.Length );  

                    fs.Close();  

                    this.tblError.Text = "File successfully saved!";  

                }  

            }  

            catch ( Exception ex )  

            {  

                this.tblError.Text = "Error getting result: " + ex.Message;  

            }  

        }

        #endregion     

    }

WCF：

  public byte[] GetFile(string fileName)
        {
            string filePath = System.Web.Hosting.HostingEnvironment.MapPath("~/DownLoad")+@"\"+fileName;
            System.IO.FileStream sr = File.OpenRead(filePath);
            byte[] data = new byte[sr.Length];

            int offset = 0;
            int remaining = data.Length;
            // 只要有剩余的字节就不停的读
            while (remaining > 0)
            {
                int read = sr.Read(data, offset, remaining);
                if (read <= 0)
                {

                    break;
                }
                // 减少剩余的字节数
                remaining -= read;
                // 增加偏移量
                offset += read;
            }
            sr.Close();
            return data;

        }