Creating events in VB.net

11 Apr 2005 3:35 PM

Jeffrey Spoon

Hello. I have been working on the program below. However I'm not sure
how to get my own event working properly. I created my ThresholdNormal
class and put a condition in the sub CheckThreshold. It then raises the
ThresholdOK event. My event handler Private Sub Threshold_Normal should
then run the EnterState7() sub. But the event is never raised and
judging from the fact that the label4 test I included doesn't update the
CheckThreshold() sub is never called. And I've no idea why. Any help
appreciated (sorry about the reams of code).

Code:

Form1:

Private StateVariableA As Integer 'A Main State
    Private StateVariableB As Integer 'B Alarm substate
    Private StateVariableBHistory As Integer    'B alarm substate
history
    Protected Reading As Integer        'getReading variable
    Protected LowerThreshold = 60         'thresholds
    Protected UpperThreshold = 80
    Protected count = -1          'debug
    Private WithEvents Threshold As ThresholdNormal

      Private Sub EnterState1()
        'This is the Bed Empty (Default) State
        'No patient in bed
        StateVariableA = 1
        StateAlbl.Text = StateVariableA
        '
        HeartRatelbl.Text = "Bed empty"
        DataLogger.SetThresholds(LowerThreshold, UpperThreshold)
        DataLogger.FastSpeed()
    End Sub

    Private Sub EnterState2()
        'This is the Disable Alarm State
        'Patient in bed
        StateVariableB = 2
        StateBlbl.Text = StateVariableB
        '
        DataLogger.SetDisableAlarm(True)
        AlarmEnablebtn.Text = "Enable Alarm"
    End Sub

    Private Sub EnterState3()
        'This is the Update Heart Rate State
        'Responds to getReading event
        StateVariableA = 3
        StateAlbl.Text = StateVariableA
        '
        Reading = DataLogger.GetReading
        ' If Reading <= UpperThreshold And Reading >= LowerThreshold
Then
        'Alarmlbl.Text = "Should be normal"
        'End If
        HeartRatelbl.Text = Reading
        '
        count = count + 1
        countlbl.Text = count
        Threshold.CheckThreshold()

    End Sub

    Private Sub EnterState4()
        'This is the Alarm Enabled State
        'Responds to Alarm Enabled event
        StateVariableB = 4
        StateBlbl.Text = StateVariableB
        '
        DataLogger.SetDisableAlarm(False)
        AlarmEnablebtn.Text = "Disable Alarm"
    End Sub

    Private Sub EnterState5()
        'This is the Alarm Substate
        'This deals with State 5B
        StateVariableA = 5
        StateAlbl.Text = StateVariableA
        EnterState2()
    End Sub

    Private Sub EnterState6()
        'This is the Alarm activated state
        '
        StateVariableA = 6
        StateAlbl.Text = StateVariableA
        Alarmlbl.Text = "Threshold Exceeded"
    End Sub

    Private Sub EnterState7()
        'This is the alarm reset (de-activate) state
        '
        StateVariableA = 7
        StateAlbl.Text = StateVariableA
        Alarmlbl.Text = "Threshold Normal" 'reset alarm
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
        'Form load event
        Threshold = New ThresholdNormal
        EnterState1()
    End Sub

    Private Sub Patient_Bed_toggle(ByVal sender As System.Object, ByVal
e As System.EventArgs) Handles PatientInbtn.Click

        If StateVariableA = 1 Then
            EnterState5()
        End If

    End Sub

    Private Sub Reading_Ready_get(ByVal sender As System.Object, ByVal e
As System.EventArgs) Handles DataLogger.NextReadingReady
        'NextReadingReady() event handler

        If StateVariableA = 5 Then
            EnterState3()
        ElseIf StateVariableA = 3 Then
            EnterState3()
        ElseIf StateVariableA = 6 Then
            EnterState3()
        ElseIf StateVariableA = 7 Then
            EnterState3()
        End If
    End Sub

    Private Sub Alarm_Toggle_click(ByVal sender As System.Object, ByVal
e As System.EventArgs) Handles AlarmEnablebtn.Click
        'Alarm Enabled/Disabled event handler

        If StateVariableB = 2 Then
            StateVariableBHistory = 2
            StateBHlbl.Text = StateVariableBHistory
            EnterState4()
        ElseIf StateVariableB = 4 Then
            StateVariableBHistory = 4
            StateBHlbl.Text = StateVariableBHistory
            EnterState2()
        ElseIf StateVariableA = 6 Then
            EnterState5()
        ElseIf StateVariableA = 7 Then
            EnterState5()
        ElseIf StateVariableA = 3 Then
            If StateVariableBHistory = 2 Then
                EnterState2()
            ElseIf StateVariableBHistory = 4 Then
                EnterState4()
            End If
        End If
    End Sub

    Private Sub Upper_Threshold_exceed(ByVal sender As System.Object,
ByVal e As System.EventArgs) Handles DataLogger.UpperThresholdExceeded
        'Upper threshold exceeded event handler

        If StateVariableA = 7 Then
            EnterState6()
        ElseIf StateVariableB = 4 Then
            EnterState6()
        ElseIf StateVariableA = 3 Then
            EnterState6()
        End If

    End Sub

    Private Sub Lower_Threshold_exceed(ByVal sender As System.Object,
ByVal e As System.EventArgs) Handles DataLogger.LowerThresholdExceeded
        'Lower threshold exceeded event handler

        If StateVariableA = 7 Then
            EnterState6()
        ElseIf StateVariableB = 4 Then
            EnterState6()
        ElseIf StateVariableA = 3 Then
            EnterState6()
        End If

    End Sub

    Private Sub Threshold_Normal() Handles Threshold.ThresholdOK
        If StateVariableA = 6 Then
            EnterState7()
            If StateVariableA = 3 Then
                EnterState7()
            End If
        End If
    End Sub

End Class

Class ThresholdNormal
    Inherits Screen1

    Public Event ThresholdOK()

    Public Sub CheckThreshold()
        If Reading <= UpperThreshold And Reading >= LowerThreshold Then
            RaiseEvent ThresholdOK()

        End If
        Label4.Text = Reading
        Label4.Text = "hello"
    End Sub

End Class

--
Jeffrey Spoon

11 Apr 2005 3:53 PM

JohnFol

The class that generates the events is based upon inheriting Screen1, but
it's not clear from the listing what this is, if it over rides anything etc.

Can I suggest you stick a break points in on the line Public Sub
CheckThreshold()
and add a simple try catch block. Then step through the code to see if it
gets as far as RaiseEvent ThresholdOK()

Show quoteHide quote

"Jeffrey Spoon" <JeffreySp***@hotmail.com> wrote in message
news:TgCQZ8BrkpWCFwSL@nowhere.nnn...
>
>
> Hello. I have been working on the program below. However I'm not sure
> how to get my own event working properly. I created my ThresholdNormal
> class and put a condition in the sub CheckThreshold. It then raises the
> ThresholdOK event. My event handler Private Sub Threshold_Normal should
> then run the EnterState7() sub. But the event is never raised and
> judging from the fact that the label4 test I included doesn't update the
> CheckThreshold() sub is never called. And I've no idea why. Any help
> appreciated (sorry about the reams of code).
>
> Code:
>
> Form1:
>
> Private StateVariableA As Integer 'A Main State
>    Private StateVariableB As Integer 'B Alarm substate
>    Private StateVariableBHistory As Integer    'B alarm substate
> history
>    Protected Reading As Integer        'getReading variable
>    Protected LowerThreshold = 60         'thresholds
>    Protected UpperThreshold = 80
>    Protected count = -1          'debug
>    Private WithEvents Threshold As ThresholdNormal
>
>
>      Private Sub EnterState1()
>        'This is the Bed Empty (Default) State
>        'No patient in bed
>        StateVariableA = 1
>        StateAlbl.Text = StateVariableA
>        '
>        HeartRatelbl.Text = "Bed empty"
>        DataLogger.SetThresholds(LowerThreshold, UpperThreshold)
>        DataLogger.FastSpeed()
>    End Sub
>
>    Private Sub EnterState2()
>        'This is the Disable Alarm State
>        'Patient in bed
>        StateVariableB = 2
>        StateBlbl.Text = StateVariableB
>        '
>        DataLogger.SetDisableAlarm(True)
>        AlarmEnablebtn.Text = "Enable Alarm"
>    End Sub
>
>    Private Sub EnterState3()
>        'This is the Update Heart Rate State
>        'Responds to getReading event
>        StateVariableA = 3
>        StateAlbl.Text = StateVariableA
>        '
>        Reading = DataLogger.GetReading
>        ' If Reading <= UpperThreshold And Reading >= LowerThreshold
> Then
>        'Alarmlbl.Text = "Should be normal"
>        'End If
>        HeartRatelbl.Text = Reading
>        '
>        count = count + 1
>        countlbl.Text = count
>        Threshold.CheckThreshold()
>
>    End Sub
>
>    Private Sub EnterState4()
>        'This is the Alarm Enabled State
>        'Responds to Alarm Enabled event
>        StateVariableB = 4
>        StateBlbl.Text = StateVariableB
>        '
>        DataLogger.SetDisableAlarm(False)
>        AlarmEnablebtn.Text = "Disable Alarm"
>    End Sub
>
>    Private Sub EnterState5()
>        'This is the Alarm Substate
>        'This deals with State 5B
>        StateVariableA = 5
>        StateAlbl.Text = StateVariableA
>        EnterState2()
>    End Sub
>
>    Private Sub EnterState6()
>        'This is the Alarm activated state
>        '
>        StateVariableA = 6
>        StateAlbl.Text = StateVariableA
>        Alarmlbl.Text = "Threshold Exceeded"
>    End Sub
>
>    Private Sub EnterState7()
>        'This is the alarm reset (de-activate) state
>        '
>        StateVariableA = 7
>        StateAlbl.Text = StateVariableA
>        Alarmlbl.Text = "Threshold Normal" 'reset alarm
>    End Sub
>
>    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Load
>        'Form load event
>        Threshold = New ThresholdNormal
>        EnterState1()
>    End Sub
>
>    Private Sub Patient_Bed_toggle(ByVal sender As System.Object, ByVal
> e As System.EventArgs) Handles PatientInbtn.Click
>
>        If StateVariableA = 1 Then
>            EnterState5()
>        End If
>
>    End Sub
>
>
>
>    Private Sub Reading_Ready_get(ByVal sender As System.Object, ByVal e
> As System.EventArgs) Handles DataLogger.NextReadingReady
>        'NextReadingReady() event handler
>
>        If StateVariableA = 5 Then
>            EnterState3()
>        ElseIf StateVariableA = 3 Then
>            EnterState3()
>        ElseIf StateVariableA = 6 Then
>            EnterState3()
>        ElseIf StateVariableA = 7 Then
>            EnterState3()
>        End If
>    End Sub
>
>    Private Sub Alarm_Toggle_click(ByVal sender As System.Object, ByVal
> e As System.EventArgs) Handles AlarmEnablebtn.Click
>        'Alarm Enabled/Disabled event handler
>
>        If StateVariableB = 2 Then
>            StateVariableBHistory = 2
>            StateBHlbl.Text = StateVariableBHistory
>            EnterState4()
>        ElseIf StateVariableB = 4 Then
>            StateVariableBHistory = 4
>            StateBHlbl.Text = StateVariableBHistory
>            EnterState2()
>        ElseIf StateVariableA = 6 Then
>            EnterState5()
>        ElseIf StateVariableA = 7 Then
>            EnterState5()
>        ElseIf StateVariableA = 3 Then
>            If StateVariableBHistory = 2 Then
>                EnterState2()
>            ElseIf StateVariableBHistory = 4 Then
>                EnterState4()
>            End If
>        End If
>    End Sub
>
>    Private Sub Upper_Threshold_exceed(ByVal sender As System.Object,
> ByVal e As System.EventArgs) Handles DataLogger.UpperThresholdExceeded
>        'Upper threshold exceeded event handler
>
>        If StateVariableA = 7 Then
>            EnterState6()
>        ElseIf StateVariableB = 4 Then
>            EnterState6()
>        ElseIf StateVariableA = 3 Then
>            EnterState6()
>        End If
>
>    End Sub
>
>    Private Sub Lower_Threshold_exceed(ByVal sender As System.Object,
> ByVal e As System.EventArgs) Handles DataLogger.LowerThresholdExceeded
>        'Lower threshold exceeded event handler
>
>        If StateVariableA = 7 Then
>            EnterState6()
>        ElseIf StateVariableB = 4 Then
>            EnterState6()
>        ElseIf StateVariableA = 3 Then
>            EnterState6()
>        End If
>
>    End Sub
>
>    Private Sub Threshold_Normal() Handles Threshold.ThresholdOK
>        If StateVariableA = 6 Then
>            EnterState7()
>            If StateVariableA = 3 Then
>                EnterState7()
>            End If
>        End If
>    End Sub
>
> End Class
>
> Class ThresholdNormal
>    Inherits Screen1
>
>    Public Event ThresholdOK()
>
>    Public Sub CheckThreshold()
>        If Reading <= UpperThreshold And Reading >= LowerThreshold Then
>            RaiseEvent ThresholdOK()
>
>        End If
>        Label4.Text = Reading
>        Label4.Text = "hello"
>    End Sub
>
> End Class
>
>
> --
> Jeffrey Spoon
>

11 Apr 2005 4:17 PM

Jeffrey Spoon

In message <e4x6e.17962$il.12***@newsfe5-win.ntli.net>, JohnFol
<OutlookExpr***@WibbleObbble.Com> writes

>The class that generates the events is based upon inheriting Screen1, but
>it's not clear from the listing what this is, if it over rides anything etc.
>
>Can I suggest you stick a break points in on the line Public Sub
>CheckThreshold()
>and add a simple try catch block. Then step through the code to see if it
>gets as far as RaiseEvent ThresholdOK()
>

Sorry, I chopped off the very top of the code:

Public Class Screen1
Inherits System.Windows.Forms.Form

It's just a default form, but I have another form which is empty at the
moment, which will be used eventually. All I have done for now is made
Screen1 the start-up object in project properties.

I will try what you suggested also. Thanks for the response.

--
Jeffrey Spoon

11 Apr 2005 6:25 PM

Jeffrey Spoon

In message <e4x6e.17962$il.12***@newsfe5-win.ntli.net>, JohnFol
<OutlookExpr***@WibbleObbble.Com> writes

>The class that generates the events is based upon inheriting Screen1, but
>it's not clear from the listing what this is, if it over rides anything etc.
>
>Can I suggest you stick a break points in on the line Public Sub
>CheckThreshold()
>and add a simple try catch block. Then step through the code to see if it
>gets as far as RaiseEvent ThresholdOK()
>

Ok I've done this. It is calling CheckThreshold each time but the event
is never raised because the Reading value is always 0 for some reason. I
have inherited Screen1 (where Reading resides) and it is protected so I
thought that would've worked. Also, the reading is displayed properly on
the form. Something else I don't understand is that the label4 variable
is being updated according to the debugger but it is not being updated
on the actual form.

--
Jeffrey Spoon

11 Apr 2005 6:40 PM

Jeffrey Spoon

In message <e4x6e.17962$il.12***@newsfe5-win.ntli.net>, JohnFol
<OutlookExpr***@WibbleObbble.Com> writes

>The class that generates the events is based upon inheriting Screen1, but
>it's not clear from the listing what this is, if it over rides anything etc.
>
>Can I suggest you stick a break points in on the line Public Sub
>CheckThreshold()
>and add a simple try catch block. Then step through the code to see if it
>gets as far as RaiseEvent ThresholdOK()
>

Ok, it must have been since Reading was updated within a sub procedure
when the ThresholdNormal class was inheriting the attributes it was just
using the default declaration as it wouldn't see the local assignment.
So now I pass the reading as a parameter to the CheckThreshold(Reading)
sub and it worked fine.

The only thing I'm not sure about is why label4 is not updated. I assume
this is because it is not set on the form Screen1 but in a separate
class. Is some sort of access required in the properties somewhere or
should it just be done within the associated form?

Thanks John (I'll probably be back here shortly with more problems,
you'll be happy to know...)

--
Jeffrey Spoon