troubleshooting Question

Cross-thread operation not valid

Avatar of KJLC
KJLC asked on
Visual Basic.NET
6 Comments1 Solution647 ViewsLast Modified:
Hi I know this has been asked before but i am struggling.

I have a form with check boxes on.

I want to update these check boxes from another Class.

The class has a timer that loops around checking for updates.

However i get the error of Cross-thread operation not valid.

I was looking into delegates and invoking etc but cant seam to get it to work

Public Class FormUpdateService
    Private aTimer As System.Timers.Timer
    Private theForm As Form
    Public Sub SetupForm(ByVal currentForm As form)
        aTimer = New System.Timers.Timer(10000)
        AddHandler aTimer.Elapsed, AddressOf OnTimedEvent
        aTimer.Interval = 1000
        aTimer.Enabled = True
        theForm = currentForm
    End Sub

    Private Sub OnTimedEvent(ByVal source As Object, ByVal e As ElapsedEventArgs)
    End Sub
    Public Sub CloseForm()
        aTimer.Enabled = False
    End Sub

    Private Sub SetButtons(ByVal currentForm As Form)
        Dim localSystemSignals As SystemSignalsSingleton = SystemSignalsSingleton.GetSingleton
        Dim fControl As Control

        For Each fControl In currentForm.Controls
            If (TypeOf fControl Is CheckBox) Then
                Dim chBox As CheckBox
                Dim signals As New List(Of IOItem)
                Dim returnValue As New IOItem
                chBox = fControl
                signals = localSystemSignals.GetIOItems
                For Each signal As IOItem In signals
                    If signal.ControlName = fControl.Tag Then
                        If signal.ActualSignalValue = 1 Then
                            chBox.Checked = True
                        End If
                    End If
            End If
        Next fControl

    End Sub

End Class

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