Silverlight 3 Async File Uploader with WebControl and ASHX Receiver

Introduction

This my first article/tip here. I want to post a little guide to develop a simple "async file uploader class" for Silverlight 3. I will post the client-side code and the server-side code.

I'm really sorry about my English.

Using the Code

File upload with Silverlight can be performed in many ways, but this is the one I prefer.

Step 1 (Silverlight Application): Create the class with all the sub, function, event and....

Imports System.ComponentModel
Imports System.IO

Public Class cFileUploader

    Public Event UploadStarted(ByVal sender As cFileUploader)
    Public Event UploadCompleted(ByVal sender As cFileUploader)
    Public Event UploadProgressChanged(ByVal sender As cFileUploader, _
	ByVal currentbytes As Integer, ByVal totalbytes As Integer, _
	ByVal percentual As Integer)
    Public Event UploadFailed(ByVal sender As cFileUploader, ByVal ex As Exception)

    Dim WithEvents bgw As BackgroundWorker
    Dim WithEvents wc As WebClient

    Dim input As Stream
    Dim output As Stream
    Dim byteread As Integer = -1
    Dim bytereadcount As Integer = 0

    Public BufferLenght As Integer = 8138
    Public FileReceiverUrl As String = "http://localhost:50245/filereceiver.ashx"

    Public File As FileInfo

    Sub New(ByVal file As FileInfo)
        Me.File = file
    End Sub

    Sub New()

    End Sub

    Public Sub UploadFileAsync()
        Me.UploadFileAsync(Me.File.Name, Me.File.OpenRead)
    End Sub

    Public Sub UploadFileAsync(ByVal filename As String)
        Me.UploadFileAsync(filename.Trim, Me.File.OpenRead)
    End Sub

    Public Sub UploadFileAsync(ByVal file As FileInfo)
        Me.File = file
        Me.UploadFileAsync(Me.File.Name, Me.File.OpenRead)
    End Sub

    Public Sub UploadFileAsync(ByVal filename As String, ByVal file As FileInfo)
        Me.File = file
        Me.UploadFileAsync(filename, Me.File.OpenRead)
    End Sub

    Private Sub UploadFileAsync(ByVal filename As String, ByVal data As Stream)
        Try
            RaiseEvent UploadStarted(Me)
            Me.bgw = New BackgroundWorker
            Me.bgw.WorkerReportsProgress = True
            Me.wc = New WebClient
            Me.input = data
            Me.byteread = -1
            Me.bytereadcount = 0
            Dim ub As UriBuilder = New UriBuilder(Me.FileReceiverUrl)
            ub.Query = String.Format("filename={0}", filename)
            Me.wc.OpenWriteAsync(ub.Uri)
        Catch ex As Exception
            RaiseEvent UploadFailed(Me, ex)
        End Try
    End Sub

    Private Sub wc_OpenWriteCompleted(ByVal sender As Object, _
	ByVal e As System.Net.OpenWriteCompletedEventArgs) _
	Handles wc.OpenWriteCompleted
        Try
            Me.output = e.Result
            Me.bgw.RunWorkerAsync()
        Catch ex As Exception
            RaiseEvent UploadFailed(Me, ex)
        End Try
    End Sub

    Private Sub bgw_DoWork(ByVal sender As Object, _
	ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bgw.DoWork
        Try
            Me.bgw.ReportProgress(0)
            Dim buffer(Me.BufferLenght) As Byte
            If byteread <> 0 Then
                bytereadcount = bytereadcount + byteread
                byteread = Me.input.Read(buffer, 0, buffer.Length)
                Me.output.Write(buffer, 0, byteread)
            End If
        Catch ex As Exception
            Me.byteread = 0
            RaiseEvent UploadFailed(Me, ex)
        End Try
    End Sub

    Private Sub bgw_ProgressChanged(ByVal sender As Object, _
	ByVal e As System.ComponentModel.ProgressChangedEventArgs) _
	Handles bgw.ProgressChanged
        Try
            Dim tot As Integer = Me.File.OpenRead.Length
            Dim cur As Integer = Math.Max(bytereadcount, 0)
            Dim prc As Integer = CInt(100 * (cur / tot))
            RaiseEvent UploadProgressChanged(Me, cur, tot, prc)
        Catch ex As Exception
        End Try
    End Sub

    Private Sub bgw_RunWorkerCompleted(ByVal sender As Object, _
	ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) _
	Handles bgw.RunWorkerCompleted
        Try
            If byteread <> 0 Then
                Me.bgw.RunWorkerAsync()
            Else
                Me.output.Close()
                Me.input.Close()
                RaiseEvent UploadCompleted(Me)
            End If
        Catch ex As Exception
            RaiseEvent UploadFailed(Me, ex)
        End Try
    End Sub

End Class

Here the only thing to change is the URL of the "filereceiver.ashx" explained in STEP 2.

Step 2 (Hosting Web Site): Add to the project (the web/server side that publics the Silverlight app) a "Generic Handler" (ASHX file).

I inserted the "filereceiver.ashx" file with the following code:

Imports System.Web
Imports System.Web.Services
Imports System.IO

Public Class FileReceiver
    Implements System.Web.IHttpHandler

    Sub ProcessRequest(ByVal context As HttpContext) _
		Implements IHttpHandler.ProcessRequest
        Dim filename As String = context.Request.QueryString("filename").ToString

        Dim destFolder As String
        destFolder = Path.GetFullPath(AppDomain.CurrentDomain.BaseDirectory)
        destFolder = context.Server.MapPath("~/App_Data/FilesArchive/")
        destFolder = Path.GetFullPath("c:\temp\")

        Using inputStream As Stream = context.Request.InputStream
            Using fs As FileStream = New FileStream_
	    (destFolder + filename, FileMode.Create, FileAccess.Write, FileShare.Read)
                Dim buffer(inputStream.Length) As Byte
                inputStream.Read(buffer, 0, buffer.Length)
                fs.Write(buffer, 0, buffer.Length)
                fs.Flush()
            End Using
        End Using

    End Sub

    ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
        Get
            Return False
        End Get
    End Property

End Class

The code is quite simple. The only thing to change is the destination folder "destFolder" and apply the correct permissions of the web server application folders.

I hope you enjoy this.

Bye bye !!!