SilverLight下载任意文件技巧

xaml采用LinkButton 其NavigateUri属性链接到服务端下载的ashx文档 如 HyperlinkButton Margin="32,135,198,140" Content="HyperlinkButton" NavigateUri="http://localhost:1399/download.ashx" / download.ashx 如下 Code 1 Imports System.Web 2 Imports

xaml采用LinkButton 其NavigateUri属性链接到服务端下载的ashx文档

如

 

download.ashx如下

 

Code
 1Imports System.Web
 2Imports System.Web.Services
 3Imports System.Net
 4Public Class downloadClass download
 5    Implements System.Web.IHttpHandler
 6
 7    Private ChunkSize As Long = 102400 '100K 每次读取文件，只读取100Ｋ，这样可以缓解服务器的压力
 8
 9    Sub ProcessRequest()Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest
10        Dim fileName As String = "aaa.JPG" '客户端保存的文件名
11        Dim filePath As String = context.Server.MapPath("image/IMG_1370.JPG") '路径
12
13        Dim fileInfo As System.IO.FileInfo = New System.IO.FileInfo(filePath)
14
15        If fileInfo.Exists = True Then
16
17            Dim buffer(ChunkSize) As Byte
18
19            context.Response.Clear()
20            Dim iStream As System.IO.FileStream = System.IO.File.OpenRead(filePath)
21            Dim dataLengthToRead As Long = iStream.Length '获取下载的文件总大小
22
23            context.Response.ContentType = "application/octet-stream"
24            '通知浏览器下载文件而不是打开
25            context.Response.AddHeader("Content-Disposition", "attachment;  filename=" & _
26                               HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8))
27Loop1:
28            While dataLengthToRead > 0 And context.Response.IsClientConnected
29                Dim lengthRead As Integer = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize)) '读取的大小
30                context.Response.OutputStream.Write(buffer, 0, lengthRead)
31                context.Response.Flush()
32                dataLengthToRead = dataLengthToRead - lengthRead
33            End While
34  
35            context.Response.Close()
36            context.Response.End()
37        End If
38
39        'context.Response.ContentType = "text/plain"
40        'context.Response.Write("Hello World!")
41
42    End Sub
43
44    ReadOnly Property IsReusable()Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
45        Get
46            Return False
47        End Get
48    End Property
49
50End Class