visa namespace between forms.

[markcstephens]

I am trying to pass visa namespace between forms and I am really stuck! I cannot figure out why I can see the mainform property from the other form. Can someone give me a shove in the right direction, Please? Here is some psuedo code: namespace instcontrol class mainform Public ReadOnly Property OpenedSession() As NationalInstruments.VisaNS.MessageBasedSession     Get         Return mbSession     End Get End Property Private Sub btnOpenSession() ... mbSession = CType(ResourceManager.GetLocalManager().Open(txtSelectedResource.Text), MessageBasedSession) ... End Sub Private Sub btnOtherForm()         Dim Other as OtherForm = New OtherForm         OtherForm.ShowDialog EndSub End Class Class OtherForm Private Sub OtherForm_Load() If Not (InstrumentControl.MainForm.OpenedSession Is Nothing) Then         PopulateSessionTreeView() Else         Me.Close() End If End Sub End Class End Property

[MissyS]

Attached is an example that shows passing strings across forms. It is done for VISA resource names in the Simple Write Read example, located in the following folder.

C:\Program Files\National Instruments\MeasurementStudioVS2003\DotNET\Examples\Visa\SimpleReadWrite\VB

Check to see if your variable is public or private. In the Class View, you should see a lock if the variable is only accessible in its owning form. In the attached example, I declared a variable, PublicVariable, as public. You should be able to access it from Form1 (it is declared in Form2). The variable, TestVar, is private and is accessed to change values for the form using a property. It is not directly accessible by Form1 (it is also declared in Form2), but can be accessed through the public method. I hope this helps!

Regards,

[markcstephens]

I did find another way to do it, and after seeing your example it all made perfect sense to this poor old vb6 programmer 🙂

I did it my way comes to mind here, but your way is much simpler and elegant.

My Way:

Class Main

  Public ReadOnly Property OpenedSession() As NationalInstruments.VisaNS.MessageBasedSession
     Get
          Return mbSession
     End Get
  End Property

  Private Sub btnBrowseVisaNS_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBrowseVisaNS.Click
     Dim BrowseVisaNS As BrowseVisaNSForm = New BrowseVisaNSForm
     BrowseVisaNS.Owner = Me
     BrowseVisaNS.ShowDialog()
  End Sub
End Class

Class BrowseVisaNS
  
  Dim mbsession As MainForm
 
  Private Sub BrowseVisaNS_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
     mbsession = Me.Owner
     If Not (mbsession.OpenedSession Is Nothing) Then
          PopulateSessionTreeView()
     Else
          Me.Close()
     End If
  End Sub

End Class

Your Way:

.ShowDialog(Me)

Much less typing 🙂

Thanks for pointing me in the right direction with that one, I would have wandered around aimlessly for days before figuring it out!

[MissyS]

Glad I could help! Happy programming!

Regards,