Backgroundworker and my.computer.network.ping

Backgroundworker and my.computer.network.ping

• Gladys27216

  Just as I suspected. You are calling Ping on the UI thread.
  
  The line:

  If lvPcs.InvokeRequired Then  lvPcs.Invoke(New getpcnummerdelegate(AddressOf getpcnummer), New Object() {i})

  It is basically saying; 'if not on the user interface thread, then call this method on the user interface thread'. Which defeats the purpose of having the background worker in the first place.
  
  I would probably do something like this:
  
  

  Imports System.Net.NetworkInformation Public Class Form1  Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click   Dim urls(ListView1.Items.Count - 1) As String   For i As Integer = 0 To ListView1.Items.Count - 1    urls(i) = ListView1.Items(i).Text   Next   BackgroundWorker1.RunWorkerAsync(urls)  End Sub  Private Sub OnBackgroundWorkerDoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork   Dim urls() = CType(e.Argument, String())   For i As Integer = 0 To urls.Length - 1    Dim success As Boolean = False    Try     success = My.Computer.Network.Ping(urls(i))    Catch ex As PingException    Catch ex As InvalidOperationException    End Try    BackgroundWorker1.ReportProgress(i, success)   Next  End Sub  Private Sub OnBackgroundWorkerProgressChanged(ByVal sender As System.Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged   If e.UserState = True Then    ListView1.Items(e.ProgressPercentage).ImageIndex = 0   Else    ListView1.Items(e.ProgressPercentage).ImageIndex = 1   End If  End Sub End Class

  
  
  This assumes that you have:
  
  1. A Button control named Button1
  2. A ListView control named ListView1
  3. A BackgroundWorker component named BackgroundWorker1

  
  
  

• jjones11

  Can you post the code you are using I tried just this and it worked fine.
  
  Are you calling Ping in the DoWork handler
  
  

• Chuck McD

  Private Sub Controlleur_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles Controlleur.DoWork         Dim i As Integer         Dim delay As Integer         delay = Convert.ToInt32(e.Argument)         While lopen = True             If aantalpcs > 0 Then                 For i = 0 To aantalpcs - 1 Step +1                     getpcnummer(i)                     Controlleur.ReportProgress(0, i)                 Next                 draad.Sleep(delay)             End If         End While     End Sub

  
  
  

  Private Sub getpcnummer(ByVal i As Integer)         If lvPcs.InvokeRequired Then             lvPcs.Invoke(New getpcnummerdelegate(AddressOf getpcnummer), New Object() {i})         Else             Dim adres As String = lvPcs.Items(i).Text             Dim gevonden As Integer             If My.Computer.Network.IsAvailable Then                 If controle(adres) Then                     gevonden = 0                 Else                     gevonden = 1                 End If             Else                 gevonden = 1             End If             setstatus(gevonden, i)         End If     End Sub

  
  
  

  Private Function controle(ByVal adres As String) As Boolean         If My.Computer.Network.Ping(adres, 0) Then             Return True         Else             Return False         End If     End Function

  
  
  

  Private Sub setstatus(ByVal gevonden As Integer, ByVal i As Integer)         If gevonden = 1 Then             lvPcs.Items(i).ImageIndex = 1         Else             lvPcs.Items(i).ImageIndex = 0         End If     End Sub

  
  
  therre you go
  
  

• Ivan Andrade

  Thanks for the explanation, it works perfectly now :)
  
  greets
  
  
• Backgroundworker and my.computer.network.ping