Need help rewriting a foreach and do until loop - vb.net

Question

So i am trying to recode this because its not working correctly :
Private Sub StartTrafficExchange()
Dim downloadstring As New StreamReader(Response2.GetResponseStream())
Dim filterstring As String() = downloadstring.ReadToEnd.Split("|")
For Each stirngman As String In filterstring
linklist.Items.Add(stirngman)
Next
Do Until linklist.Items.Count = 0
Dim rand As New Random
linklist.SelectedIndex = rand.Next(0, linklist.Items.Count - 1)
Dim strimgna As String = linklist.SelectedItem
Dim newlinkstring As String() = strimgna.Split("``")
For Each stringma As String In newlinkstring
If stringma.Length < 8 Then
GoTo a
Else
LabelX1.Text = "Navigating To " + stringma
stringma = stringma.Replace("[TIER4]", "")
Debug.WriteLine(stringma)
WebKitBrowser1.Navigate(strimgna)
Thread.Sleep(15000)
End If
LabelX1.Text = "Navigating To " + stringma
ProgressBarX1.Value += 1 a:
Next
linklist.Items.Remove(linklist.SelectedItem)
Loop
ProgressBarX1.Maximum = linklist.Items.Count
ProgressBarX1.Value = 0
StartTrafficExchange()
End Sub
So what does the code do ? Well it fetches a webrequest to a link where the source will be like
http://www.asdfd.com``[TIER4]|http://aesde.com``[TIER4]|http://www.excaedf.com``[TIER4]|
As you can see the above code first splits "|" and adds them each to a list.
Then we split other things to make it as a perfect url and then navigate to it by webkitbrowser... and waits 15 sec by using thread.sleep (Idk if it works.) then removes it from linklist in a foreach and do until loop. So whats the problem ? Well it doesn't work correctly the webkitbrowser is just hanging .
Note : The sub StartTrafficExchange() is called when the form loads.
Can someone tell me whats wrong with the above code and is there anyother way to make this work ?
-Thanks-

Answer 1

Assuming that linklist is not an actual LinkedList but is really a List(Of T) or the list of a List control, you can replace this chunk of code:
Dim filterstring As String() = downloadstring.ReadToEnd.Split("|")
For Each stirngman As String In filterstring
linklist.Items.Add(stirngman)
Next
with this:
Dim filter As String() = downloadstring.ReadToEnd.Split("|")
linklist.AddRange(filter)
which does the same thing, only faster, and with less memory being consumed.
Next, move this way up (like immediately after the AddRange):
ProgressBarX1.Maximum = linklist.Items.Count
I was going to type out why to make the various changes, but here is the whole routine as I would refactor it:
Private Sub StartTrafficExchange()
' Performing one split here that removes everything that needs
' to go will be faster, take less memory, won't have to be
' touched as many times
Dim filter As String() = downloadstring.ReadToEnd.Split("``[TIER4]|")
linklist.AddRange(filter)
' Set your maximum value so it knows when it is full
ProgressBarX1.Maximum = linklist.Items.Count
' Create a counter to let us know how many items
' have been processed
Dim counter As Int = 0
Dim currentURL As String = String.Empty
Do While linklist.Items.Count > 0
' Get the current URL from our list
currentURL = linklist.Items(counter)
LabelX1.Text = String.Format("Navigating To [TIER4] {0}", currentURL)
LabelX1.Refresh() ' Allow the label to update
' This is only good if you have a debugger turned on
' or are running from the IDE
Debug.WriteLine(currentURL)
WebkitBrowser1.Navigate(currentURL)
' Not a good idea as it will block the UI
' from responding. If you need a delay that
' doesn't appear to lock up the UI, implement
' a timer in a loop
Thread.Sleep(15000)
' Increment the counter, then update the progressbar
counter += 1
ProgressBarX1.Value = counter
ProgressBarX1.Refresh() ' Allow the progressbar to update
Loop
' When you are through getting all of the URLs,
' clear the list just one time
linklist.Items.Clear()
' Make recursive call to this sub
' You should limit the number of recursions
' somehow so you don't run out of stack space
StartTrafficExchange
End Sub
If you want to pause the process with blocking the UI, use this:
' Create a new timer object that will run for 1/10 of second
Dim timr As New Timer(100)
' Run this for 150 times at .1 seconds will
' give you a 15 second pause and still leave
' the UI responsive
For iLoop As Integer = 0 To 150
' Start the timer for .1 seconds
timr.Start()
' This tells everything on the form to process updates
DoEvents()
Next

Answer 2

First of all, this is not very important but the code is inconsistent, you are using C# practices but you are in VB.NET, then remove all those + operator on strings appends and replace them with an &.
Second, if your purpose is to wait for the webpage to be fully loaded then using Sleep method is not the way, you need to suscribe to like an WebBrowserDocumentCompleted event of the browser control (I don't know the exact event name for a WebKitBrowser)
You can simplify things by writting a method called NavigateAndWait and use it instead of using WebKitBrowser.Navigate method.
I give you an example for a default WebBrowser control:
Private WebPageLoaded As Boolean = False
''' <summary>
''' Navigates to an url and waits the page to be loaded.
''' </summary>
''' <param name="url">Indicates the url to navigate.</param>
''' <param name="newWindow">Indicates whether the url should open into a new browser window.</param>
Private Sub NavigateAndWait(ByVal Browser As WebBrowser,
ByVal url As String,
Optional newWindow As Boolean = False)
Me.WebPageLoaded = False
AddHandler Browser.DocumentCompleted, AddressOf WebBrowserDocumentCompleted
Browser.Navigate(url, newWindow)
Do Until Me.WebPageLoaded
Application.DoEvents()
Loop
RemoveHandler Browser.DocumentCompleted, AddressOf WebBrowserDocumentCompleted
End Sub
' WebBrowser [DocumentCompleted]
Private Sub WebBrowserDocumentCompleted(ByVal sender As Object, e As WebBrowserDocumentCompletedEventArgs)
Me.WebPageLoaded = True
End Sub
And other for a GeckoFX webbrowser:
Private WebPageLoaded As Boolean = False
''' <summary>
''' Navigates to an url and waits the page to be loaded.
''' </summary>
''' <param name="url">Indicates the url to navigate.</param>
Private Sub NavigateAndWait(Byval Browser as Gecko.GeckoWebBrowser,
Byval url As String,
Optional loadFlags As Gecko.GeckoLoadFlags = Gecko.GeckoLoadFlags.None,
Optional referrer As String = Nothing,
Optional postData As Gecko.GeckoMIMEInputStream = Nothing)
Me.WebPageLoaded = False
AddHandler Browser.DocumentCompleted, AddressOf GeckoWebBrowserDocumentCompleted
Browser.Navigate(url, loadFlags, referrer, postData)
Do Until Me.WebPageLoaded
Application.DoEvents()
Loop
RemoveHandler Browser.DocumentCompleted, AddressOf GeckoWebBrowserDocumentCompleted
End Sub
' GeckoWebBrowser [DocumentCompleted]
Private Sub GeckoWebBrowserDocumentCompleted(ByVal sender As Object, e As EventArgs)
Me.WebPageLoaded = True
End Sub