ping.sendasync memory leak

[Drewster727]

Hi All,

I'm having a strange issue with a memory leak associated with ping.sendasync. My program has a section in it that allows the user to specify X number of servers/computers to monitor. About every 30 seconds it will execute a routine that loops through the list and sends a ping asynchronously to each server/computer.

If I keep an eye on the process memory usage in the task manager it will creep up about 1-1.5MB each time the routine is executed. Now, this program will be used and left running for hours and hours for each person, and over the course of the day the mem usage can creep up close to a gig...... (it happened the other day until I noticed it)

See the code below for an idea of what I'm doing, note that I AM calling .dispose and in the async case I am directcasting idisposable first and then disposing as recommended on several other sites. I'm also telling the GC to collect after as well.

Server Indicators routine (starts the ping.sendasync):

Public Sub ServerIndicators()
        ReloadingServers = True

        ServerStatusDG.Sort(ServerStatusDG.Columns(ServerStatusDG.Columns.Item("ServerName").Index), ListSortDirection.Ascending)

        Dim myPing As New Ping
        For Each ipAddy As String In My.Settings.ServerStatusCollection
            ' Generate the request
            myPing = New Ping()
            ' Add the handler for this request...
            AddHandler myPing.PingCompleted, AddressOf PingRequestCompleted
            myPing.SendAsync(ipAddy, 1000, ipAddy)
            CType(myPing, IDisposable).Dispose()
            myPing = Nothing
        Next
        If Not ServerStatusDG.SelectedRows.Count > 0 Then
            ServerStatusDG.ClearSelection()
        End If
        GC.Collect()
        ReloadingServers = False
    End Sub

PingrequestCompleted: (check if online - loop through dgv and update that server, else report offline and find it in the dgv)

Public Sub PingRequestCompleted(ByVal sender As Object, ByVal e As Net.NetworkInformation.PingCompletedEventArgs)
        ' When received, add the approrpiate entry into the dgv
        Try
            If e.Error IsNot Nothing Then
                GoTo offline
            End If

            If e.Reply.Status = 0 Then
                'set green arrow
                If ServerStatusOfflineArray.Contains(e.UserState.ToString) Then
                    ServerStatusOfflineArray.Remove(e.UserState.ToString)
                End If
                For i = 0 To ServerStatusDG.Rows.Count - 1
                    If ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerName").Index).Value = e.UserState.ToString Then
                        If Not ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerStatusimg").Index).Value Is My.Resources.SuccessGreen Then
                            ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerStatusimg").Index).Value = My.Resources.SuccessGreen
                        End If
                        ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("FavoritesIPAddress").Index).Value = e.Reply.Address
                        If e.Reply.RoundtripTime > 100 Then
                            ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerLatency").Index).Style.ForeColor = Color.IndianRed
                            ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerLatency").Index).Value = e.Reply.RoundtripTime & "ms"
                        Else
                            ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerLatency").Index).Style.ForeColor = Color.LimeGreen
                            If e.Reply.RoundtripTime = 0 Then
                                ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerLatency").Index).Value = "<1ms"
                            Else
                                ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerLatency").Index).Value = e.Reply.RoundtripTime & "ms"
                            End If
                        End If
                        Exit For
                    End If
                Next
                GoTo skip
            Else
                GoTo offline
            End If
offline:
            'set red image

            For i = 0 To ServerStatusDG.Rows.Count - 1
                If ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerName").Index).Value = e.UserState.ToString Then
                    ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerStatusimg").Index).Value = My.Resources.ErrorRed
                    ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerStatusimg").Index).Value = Nothing
                    ServerStatusDG.Rows(i).Cells(ServerStatusDG.Columns.Item("ServerLatency").Index).Value = Nothing
                    Exit For
                End If
            Next

If Not ServerStatusOfflineArray.Contains(e.UserState.ToString) Then
                If My.Settings.OfflineAlerts = True Then
                    nfi.BalloonTipIcon = ToolTipIcon.Error
                    nfi.BalloonTipTitle = "Offline Alert"
                    nfi.BalloonTipText = e.UserState.ToString & " is not responding!"
                    nfi.ShowBalloonTip(30000)
                End If
                ServerStatusOfflineArray.Add(e.UserState.ToString)
            End If
skip:
            If ServerStatusOfflineArray.Count = 0 Then
                vNavPaneServerStatus.Image = Nothing
                vNavPaneServerStatus.HeaderText = "Favorites"
            Else
                vNavPaneServerStatus.Image = My.Resources.errorRedDot_navpane
                vNavPaneServerStatus.HeaderText = "Favorites - " & ServerStatusOfflineArray.Count & " Offline"
            End If
            vNavPaneServerStatus.Refresh()

            If Not ServerStatusDG.SelectedRows.Count > 0 Then
                ServerStatusDG.ClearSelection()
            End If
        Catch ex As Exception
        Finally
            CType(sender, IDisposable).Dispose()
        End Try


    End Sub

So it will loop through a datagridview and update the values each time... anything you guys can think of will help. I only started having this problem when I switched to ping.sendasync method.

I have seen this blog post about this problem... but implementing that seemed to do nothing: http://blogs.msdn.com/b/joncole/arch...sendasync.aspx

Thanks!

[Drewster727]

Any ideas guys??

[Negative0]

Could it be because you are creating one that you don't dispose? Look at the top of your method, you Dim myPing as New Ping and then in your loop you create another one, essentially orphaning that first one. Trying changing it to Dim myPing as Ping and see if that helps.

[Drewster727]

Thanks for the reply,

unfortunately the problem still exists... each time it loops through the list the process mem usage jumps about 1MB...

here is my loop adjusted:

For Each ipAddy As String In My.Settings.ServerStatusCollection
            Dim myPing As New Ping
            ' Add the handler for this request...
            AddHandler myPing.PingCompleted, AddressOf PingRequestCompleted
            myPing.SendAsync(ipAddy, 1000, ipAddy)
            CType(myPing, IDisposable).Dispose()
            myPing = Nothing
        Next

[formlesstree4]

Kind of a pointless loop. You should be disposing in the PingRequestCompleted sub. It should pass the sender along with it, allowing you to dispose of it and set it to nothing.

[Drewster727]

thanks for the response,

I actually am running dispose in the pingrequestcompleted routine.

CType(sender, IDisposable).Dispose()

the mem usage is still creeping up...

Anyone have any ideas?? this one is bothering me.. pingasync would work really well if I wasnt having this problem haha

[Drewster727]

also added this on at the end of my pingrequestcompleted routine:

With DirectCast(sender, Ping)
                RemoveHandler .PingCompleted, AddressOf PingRequestCompleted
                .Dispose()
            End With

still have the memory leak...

[ForumAccount]

Try removing the handler and calling GC.Collect() in the completed stub.