[RESOLVED] Downloading multiple files using threads

[MadCatVB]

Private Sub btn_DownalodViaHashtable_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_DownalodViaHashtable.Click

        Dim sFolderPath As String

        If FolderBrowserDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
            sFolderPath = FolderBrowserDialog1.SelectedPath

            For i As Integer = 0 To clb_Links.CheckedIndices.Count - 1 Step 1
                propLinkArray.Add(clb_Links.CheckedItems.Item(i).ToString)
            Next

            For i As Integer = 0 To propLinkArray.Count - 1 Step 1

                propURL = propLinkArray.Item(i).ToString
                propSavePath = sFolderPath

                Dim t As New Threading.Thread(AddressOf getFileHashTable)
                Hashtable.Synchronized(Me.ht_ThreadData).Add(t, propURL)
                t.Start()
            Next

        Else
            'Dialogbox has been cancelled
            Exit Sub
        End If

    End Sub

    Private Sub getFileHashTable()

        Dim threadData As Hashtable = Hashtable.Synchronized(Me.ht_ThreadData)
        'Get the data for this thread.
        Dim data As String = DirectCast(threadData(Threading.Thread.CurrentThread), String)

        'Code for downloading the file (called by each thread)
        Dim wc_MyWebClient As New WebClient
        wc_MyWebClient.DownloadFile(data, propSavePath & "\" & Path.GetFileName(data))
        wc_MyWebClient.Dispose()

        'Remove the data for this thread
        threadData.Remove(Threading.Thread.CurrentThread)

    End Sub

OK, a little update. After some perseverence i've found a way to get the downloads working and what seems like threaded properly.

The array that i was adding to the hashtable as the value containing the file URL and the save path was not working as it was supposed to.

I'd still like to know why this is the case if anyone knows.

I now have to try and set it up so that only a specified number of downloads (threads) are run simultaneously. It worked bfore using the array and i have got some code that initially counts the entries in the hash table to find if is possible to add any more threads.

    Private Sub checkHashTable()

        Dim threadData As Hashtable = Hashtable.Synchronized(Me.ht_ThreadData)
        'Check the length of the Hashtable first of all to see if there is space for any new
        'entries.
        If ht_ThreadData.Count < 3 Then
            'MsgBox(ht_ThreadData.Count)
            'There is an empty slot waiting to be filled. The element available
            'is the count.
            propActiveArrayElement = ht_ThreadData.Count
            propThreadAvailable = True

        End If


    End Sub

What i need to check for after any empty locations is if there are any threads that have finished running and do not flag up as IsAlive.

How would i go about accessing the threads in the hashtable entries to check this.

Thanks

[congminh6]

Hi,

where you do define ht_ThreadData in your code? I had errors in this code
Dim threadData As Hashtable = Hashtable.Synchronized(Me.ht_ThreadData)

Error 1 'ht_ThreadData' is not a member of 'A.frmMain'.

pls help, i'm new in vb.

thanks