MVC (Model-View-Controller) implementation in VB.NET

[matt_1ca]

I am wondering what I am missing in the attached code that is making it impossible for me to make the VB.NET program below work using MVC (Model-View-Controller).

Right now, I am really lost despite my best efforts...

I am trying to implement the observer pattern and think that my code is getting closer to MVC but not quite there yet, firstly because it wont even run ... nevertheless I know that there is someone out there who knows what I am doing wrong
and I would definitely benefit from any guidance or help that someone more experienced in MVC VB.NET implementation can
give .. hence this letter.

So far Im really stumped and would forever be grateful for any help you could give.

Gratefully,
Matt

P.S.
I think the original post did not make it as when I try to search using the name of the one who posted the thread I dont get any result returned .... in that post I experimented using attachment ... looks like there is a problem with using attachment so I am redoing the posting here and this time not using any attachment and instead I have copy pasted all the source code here as shown below ... thanks

'''first interface the subject interface

Interface Isubject
    Sub registerobserver(Iobserver o)
    sub removeobserver(Iobserver o)
    Sub notifyobservers()
End Interface


'''second interface the observer interface

Interface Iobserver
    Sub update()
End Interface

'''1st class
Imports Autodesk.AutoCAD.Interop
Imports AutocadMAP
Imports Scripting

Public Class AutoCADaccess
    Private ThisDrawing As AcadDocument
    Private DrawingName As String

    Public Sub AutoCADaccess() implements Isubject
        Iobserver = New ArrayList
    End Sub

    public sub registerObserver(Iobserver o)
        Iobserver.add(o)
    End Sub

    Public Function connectDrawing() As AcadDocument
        Dim AcadApp As AcadApplication
        Dim DrawingTitle As String
        If ThisDrawing Is Nothing Then
            On Error Resume Next
            Err.Clear()
            AcadApp = GetObject(, "AutoCAD.Application")
            If Err.Number Then 'need to create object
                AcadApp = CreateObject("AutoCAD.Application")
            End If

            AcadApp.Visible = True
            ThisDrawing = AcadApp.ActiveDocument
            AcadApp.WindowState = Common.AcWindowState.acMax
            ThisDrawing.WindowState = Common.AcWindowState.acMax

        End If

        connectDrawing = ThisDrawing

    End Function


    Public Function setDrawingTitle() As String
        Dim ObtainedTitle As String
        ObtainedTitle = ThisDrawing.GetVariable("dwgname")
        Me.DrawingName = "Title Block [" & ObtainedTitle & "]"
    End Function

End Class

'''2nd class

Imports Autodesk.AutoCAD.Interop
Imports AutocadMAP
Imports Scripting

Public Class AutoCADtitle
    Public Shared Sub main()
        Static ThisDrawing As AcadDocument
        Dim acad As New AutoCADaccess
        Dim AcadMap As AcadMap

        With acad
            ThisDrawing = .connectDrawing
        End With

        MsgBox("Title Block [" & ThisDrawing.GetVariable("dwgname") & "]")
    End Sub

End Class


'''the form which I am trying to have absorb in its caption the drawing name of the current drawing
Option Explicit On 

Imports Autodesk.AutoCAD.Interop
Imports AutocadMAP
Imports Scripting

Public Class frmTitleBlk
    Inherits System.Windows.Forms.Form

end Class

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
''''  THE GOAL, IE.. THAT OF GRABBING THE NAME OF THE           '
''''  CURRENT DRAWING AND PUTTING IT IN THE CAPTION OF          '
''''  THE LOADED FORM (frmTitle) IS EASY TO IMPLEMENT IF ONLY WE'
''''  ARE NOT DICTATED TO USE MVC ... IN THE LONG RUN           ' 
''''  I GUESS MVC ARCHITECTURE IS GOOD  SO I AM TRYING          '
''''  TO BUILD THE THING USING IT ... ANYHOW, THE WAY           '
''''  I ORIGINALLY WROTE THE PROGRAM IS SHOWN BELOW WHICH       '
''''  I HAVE MODIFIED TO THAT WHICH IS SHOWN ABOVE              '
''''  IE..THE ABOVE IS MOVING TOWARDS MVC .. BUT IN THE         '
''''  ABOVE I AM NOT EVEN SURE IF I CAN DO frmTitleBlk.show from'
''''  from the sub called main without breaking MVC rules       '
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''


Imports Autodesk.AutoCAD.Interop
Imports AutocadMAP
Imports Scripting

Public Class AutoCADaccess
    Private ThisDrawing As AcadDocument

    Public Function connectDrawing() As AcadDocument
        Dim AcadApp As AcadApplication

        If ThisDrawing Is Nothing Then
            On Error Resume Next
            Err.Clear()
            AcadApp = GetObject(, "AutoCAD.Application")
            If Err.Number Then 'need to create object
                AcadApp = CreateObject("AutoCAD.Application")
            End If

            AcadApp.Visible = True
            ThisDrawing = AcadApp.ActiveDocument
            AcadApp.WindowState = Common.AcWindowState.acMax
            ThisDrawing.WindowState = Common.AcWindowState.acMax

        End If

        connectDrawing = ThisDrawing

    End Function

End Class


'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Option Explicit On 

Imports Autodesk.AutoCAD.Interop
Imports AutocadMAP
Imports Scripting

Public Class frmTitleBlk
    Inherits System.Windows.Forms.Form

    Private Sub TitleBlk_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim ThisDrawing As AcadDocument
        Dim acad As New AutoCADaccess
        Dim AcadMap As AcadMap

        With acad
            ThisDrawing = .connectDrawing
        End With
        Me.Text = "Title Block [" & ThisDrawing.GetVariable("dwgname") & "]"
    End Sub

End Class

[dglienna]

First, using AutoCAD might cause it's own problems, but the main thing is that you forgot your CODE TAGS.

' Like This

Go back and edit your post to correct the problem, and someone can take a look at the details. Too hard to read like that.

[matt_1ca]

Thanks ...

I have tried to re-attach the VB.NET source codes here in a zip file which has two
folders the second folder is the one that has my latest attempt:

"Second Try trying Implementing MVC using Observer Pattern still far from success"

My first attempt at implementing it is shown in the folder:

"First Try Implementing MVC no good"

Thanks again, I really appreciate it.

Gratefully,
Matt

[Shuja Ali]

Matt, I had this link bookmarked long time back. May be you should go through this once and see how it is done in the example that he has shown. Al though it is little old, but I guess you can still use it
http://www.devx.com/dotnet/Article/10186

[dglienna]

Just read this a while back: http://msdn.microsoft.com/en-us/magazine/cc337884.aspx

[matt_1ca]

Thank you for your valuable answer, the link is enlightening indeed and has filled in many of the gaps in most of the materials I have.

Gratefully,
Matt

[dglienna]

Technet has a lot of info, and the blogs in general are focues on separate topics about everything