Check proxy's from listbox - vb.net

Question

So i have a listbox that i have there for a list of proxies. I have 4 buttons pertaining to it. they are find, load, save and check
I have the first 3 finished and working but i haven't found anything useful pertaining to checking the proxies, the only one that i found took like 6 seconds per proxy so it took a lot of time for a decent sized list.
So how could i make it that on the press of that button, it checks all of the proxies in the listbox and it deletes the slow ones and the ones that flat out do not work. and does this at a decent pace(so it would probably be multi threaded)
and since i can not figure this out i have no code pertaining to this except for the sub for the button click i do not feel there is a need to post code

Answer 1

My suggestion for you is :
1)use a timer control and set it's Tick property to an appropriate value such 500;
2) create an array of BackGroudWorkers for example BackGroudWorker[20];
3)when your app start run all BackGroudWorkers in array and in tick event of Timer check if any of this BackGroudWorker completed or not.If completed and you have other item in list then run it with new Item.Do this until all list Items checked

Answer 2

Public Shared Function CheckProxy(ByVal Proxy As String) As Boolean
Dim prx As Uri = Nothing
If Uri.TryCreate(Proxy, UriKind.Absolute, prx) Then
Return CheckProxy(prx)
ElseIf Uri.TryCreate("http://" & Proxy, UriKind.Absolute, prx) Then
Return CheckProxy(prx)
Else
Return False
End If
End Function
Public Shared Function CheckProxy(ByVal Proxy As Uri) As Boolean
Dim iProxy As Socket = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
iProxy.ReceiveTimeout = 500 : iProxy.SendTimeout = 500
Try
'' Connect using a timeout (1/2 second)
Dim result As IAsyncResult = iProxy.BeginConnect(Proxy.Host, Proxy.Port, Nothing, Nothing)
Dim success As Boolean = result.AsyncWaitHandle.WaitOne(500, True)
If (Not success) Then
iProxy.Close() : Return False
End If
Catch ex As Exception
Return False
End Try
Dim bytData() As Byte, strData As String
Dim iDataLen As Integer = 1024
strData = String.Format("CONNECT {0}:{1} HTTP/1.0{2}{2}", "www.google.com", 80, vbNewLine)
bytData = System.Text.ASCIIEncoding.ASCII.GetBytes(strData)
If iProxy.Connected Then
iProxy.Send(bytData, bytData.Length, SocketFlags.None)
ReDim bytData(1024)
Do
Try
iDataLen = iProxy.Receive(bytData, bytData.Length, SocketFlags.None)
Catch ex As Exception
iProxy.Close() : Return False
End Try
If iDataLen > 0 Then
strData = System.Text.ASCIIEncoding.ASCII.GetString(bytData)
Exit Do
End If
Loop
Else
Return False
End If
iProxy.Close()
Dim strAttribs() As String
strAttribs = strData.Split(" "c)
If strAttribs(1).Equals("200") Then
Return True
Else
Return False
End If
End Function
You should manage your code for threads etc, as suggested by #Nima for your proxy checking problem I have 2 methods here One asks proxy string and tries to connect it.
e.g.
ProxyStatus = CheckProxy("http://192.168.1.1:8080/")
ProxyStatus is True/False depending on if proxy works or Not