Kedaman - Master in Class Module

[Shark]

Kedaman!

If I made a function in a class module and compile it into a dll, how do I use it. A co-worker of mine, told me that it would be use like the way how I call an API.

Can you give me an example of a compile class module into a dll?

[parksie]

I'm not kedaman, but here goes:

The class modules in an ActiveX DLL are exposed as COM objects, so using the References dialogue, add a reference to the newly created DLL. You can then use the objects as if they were class modules in your own project.

[HeSaidJoe]

Open a new project (ActiveX.dll) type instead of standard
Go to the project Properties and name it accordingly.
When this opens it has a Class1 without code
Copy this code into the code section:

set the name property of the class1 to clsElasticForms
'save as clsElasticForms

Option Explicit

' Title:    Elastic Forms
' Author:   Leigh Bowers
' Email:    [email protected]
' WWW:      http://www.esheep.freeserve.co.uk/compulsion
' Version:  1.01
' Date:     19th June 1999
' Requires: N/A
' License:  Freely Distributable (non-commercial use)

Public fForm As Form

Public lOriginalWidth As Long
Public lOriginalHeight As Long

Public lMinWidth As Long
Public lMinHeight As Long

Public Type udtControl
    lLeft As Long
    lTop As Long
    lWidth As Long
    lHeight As Long
End Type
Private aControls() As udtControl

Private Property Let Form(ByVal fPassForm As Form)
    
Dim iCount As Integer
Dim cControl As Control

    Set fForm = fPassForm
    
    ' Store form's original Width & Height
    
    lOriginalWidth = fForm.Width
    lOriginalHeight = fForm.Height

    ' Use error trapping to ignore components that don't
    ' support certain properties being read at run-time

    On Error Resume Next

    ' Store the form's component's properties

    iCount = 0
    ReDim aControls(fForm.Controls.Count)

    For Each cControl In fForm.Controls
        iCount = iCount + 1
        With aControls(iCount)
            If TypeOf cControl Is Line Then
                .lLeft = cControl.X1
                .lTop = cControl.Y1
                .lWidth = cControl.X2
                .lHeight = cControl.Y2
            Else
                .lLeft = cControl.Left
                .lTop = cControl.Top
                .lWidth = cControl.Width
                .lHeight = cControl.Height
            End If
        End With
    Next ' Each

End Property

Public Sub FormResize()

    ' v1.01 (19/06/1999)
    '
    ' bDisableResize:
    ' Used to avoid unnecessary *recursive* resizing
    '
    ' lPreviousWidth/Height:
    ' Used to avoid unnecessary resizing

    ' Resize the form's controls

Dim iCount As Integer
Dim cControl As Control
Dim iTaskBarHeight As Integer
Dim sOriginalWidthUnit As Single
Dim sOriginalHeightUnit As Single
Static bDisableResize As Boolean
Static lPreviousWidth As Long
Static lPreviousHeight As Long

    If fForm Is Nothing Or bDisableResize Then Exit Sub

    ' Don't process minimized forms
    
    If fForm.WindowState = vbMinimized Then Exit Sub

    ' Check form size against minimums
    
    bDisableResize = True
    If fForm.Width < lMinWidth Then fForm.Width = lMinWidth
    If fForm.Height < lMinHeight Then fForm.Height = lMinHeight
    bDisableResize = False
    
    ' Ensure form size has changed
    
    If lPreviousWidth = fForm.Width And lPreviousHeight = fForm.Height Then Exit Sub
    lPreviousWidth = fForm.Width
    lPreviousHeight = fForm.Height

    ' Perform calculations in advance (speed increase)

    iTaskBarHeight = 28 * Screen.TwipsPerPixelY ' Standard height
    sOriginalWidthUnit = lOriginalWidth / fForm.Width
    sOriginalHeightUnit = (lOriginalHeight - iTaskBarHeight) / (fForm.Height - iTaskBarHeight)

    ' Use error trapping to ignore components that don't
    ' support certain properties being set at run-time

    On Error Resume Next

    ' Do the resize...
    
    iCount = 0

    For Each cControl In fForm.Controls
        iCount = iCount + 1
        With cControl
            If TypeOf cControl Is Line Then
                .X1 = Int(aControls(iCount).lLeft / sOriginalWidthUnit)
                .Y1 = Int(aControls(iCount).lTop / sOriginalHeightUnit)
                .X2 = Int(aControls(iCount).lWidth / sOriginalWidthUnit)
                .Y2 = Int(aControls(iCount).lHeight / sOriginalHeightUnit)
            Else
                .Left = Int(aControls(iCount).lLeft / sOriginalWidthUnit)
                .Top = Int(aControls(iCount).lTop / sOriginalHeightUnit)
                .Width = Int(aControls(iCount).lWidth / sOriginalWidthUnit)
                .Height = Int(aControls(iCount).lHeight / sOriginalHeightUnit)
            End If
        End With
    Next ' Each

End Sub


Public Sub Class_Terminate()

    Set fForm = Nothing

End Sub




Public Property Let MinWidth(ByVal lPassMinWidth As Long)

    lMinWidth = lPassMinWidth

End Property
Public Property Let MinHeight(ByVal lPassMinHeight As Long)

    lMinHeight = lPassMinHeight

End Property

'...................................................

When that is done save the project and then under file Make the project into a DLL

Once that is done Open A Standard Project and add a commandbutton and a label and a textbox..Use the default names.

'copy and paste this code into it.

Option Explicit

Private clsElastic As clsElasticForms

Private Sub Command1_Click()

Set clsElastic = Nothing
Unload Me
End Sub

Private Sub Form_Load()

'====================================================================

'this goes in the form load event of each form in app

    Set clsElastic = New clsElasticForms
    clsElastic.MinHeight = 1950
    clsElastic.MinWidth = 6960


End Sub

Private Sub Form_Resize()

clsElastic.FormResize
End Sub

Private Sub Form_Terminate()

Set clsElastic = Nothing

End Sub

Private Sub Form_Unload(Cancel As Integer)

Set clsElastic = Nothing

End Sub

Then go to your project references and use the browse button
to find the dll you just saved clsElasticForms.dll and check it off. You will be returned to your form.

Run your app and take note of it's size and spacing.

Then go to your windows desktop properties and change
your resolution.

Then rerun your application and see that it has change
it's sizes to accomodate the screen. That is because it
has used the code itn the referenced dll.

Hope you have fun with it.
Wayne

[Shark]

Thanks HeSaidJoe,

I know you went out your way to help, but do you have anything a little bit more simple to explain that process. I kind of understand that project, but do you have anything with less lines of codes in the class module so I can trace through easier?

Thanks again HeSaidJoe.

There is a tutorial about classes/user objects on this site. Read through that then ask Karl to clarify any points you need elaboration on, that's where l got the hang of the thing.

[HeSaidJoe]

Shark:
Sorry it took so long to get back...I'm at work and every now and then I actually have to work...Sucks..
anyway, here is an over simple version and I hope I don't insult you in any way or form..It is simply meant as a little spark to get you interested enough to get down and dirty and learn about this stuff. MSDN or books are helpers as well as tutorials. You can visit my links page and pick up the url of a few good vb sites and you should find turorials on most or all of them..not mine.

'open a project  activeX dll not the standard one
'it opens up with class1

'paste this code in the code section

Option Explicit


Public Sub MessageMe()
    MsgBox "Help is here, partially, anyway"
End Sub


Public Property Get cmdCaption() As String
  cmdCaption = "It's not that simple"
End Property

'save the project as whatever
'save the class1 as class1
'make the thing into a dll (same as when you make an exe
'except this one says dll

'Call your dll whatever your want


'<<<<<<<<<<<<<<  Form Code  >>>>>>>>>>>>>>>

'open a project the standard one

'create a form with 3 command buttons
'use the default names
'
'go to the project properties and change Project1  to
'MyClassProject
'
'set your reference to the dll you created
'normally it would be placed in your windows\system dir
'but it doesn't really matter for now


'this one is relatively simple
'command1 displays a message box
'from the code within the dll

'command2 changes the caption on command1
'agian from code within the dll

'command3 just unloads the form and sets the
'class = nothing to free up the memory used

Option Explicit

Public Class1 As New Class1

Private Sub Command1_Click()
    Set Class1 = New Class1
    Class1.MessageMe

End Sub

Private Sub Command2_Click()
    Set Class1 = New Class1
    Command1.Caption = Class1.cmdCaption
End Sub

Private Sub Command3_Click()
    Set Class1 = Nothing
    Unload Me
End Sub

Private Sub Form_Activate()
    Command1.Width = 3000
    Command1.Height = 500
    Command2.Height = 500
    Command2.Width = 3000
    Command1.Left = 240
    Command2.Left = 240
    Command3.Left = 1080
    Command1.Top = 120
    Command2.Top = 720
    Command3.Top = 1320
    Form1.WindowState = 0
    
    Form1.Width = 3585
    Form1.Height = 2340
End Sub

[Shark]

Thanks for the advice Jethro.

HeSaidJoe... I don't know how to express my appreciation for your generosity and time. You are the best!

[Shark]

Your example works fabulously. I have one more question. How come you want it me to do this?

'go to the project properties and change Project1 to
'MyClassProject

Thanks again HeSaidJoe.

[V(ery) Basic]

I'm not HeSaidJoe (unless I have a multiple personality disorder which I don't know about), however, adding a reference to the DLL tells VB that whenever you use something in 'MyClassProject' that it should use the MyClassProject DLL. Otherwise, VB doesn't know what any of the functions using MyClassProject mean since they aren't in the project.

[kedaman]

uh, i'm not HeSaidJoe, but i (maybe i am, funny idea V(ery)) but i saw my name and thought that i would have to drop a comment
You shouldn't mix up ActiveX Dll's with APi Dll's, they are refered with declaration statements to particular functions and subs, but by refering activeX Dll's (you check the box or browse for it in references) you can use any class (that are public in the dll, you put the methods in the classes of course.

By pressing F2, object browser appears, and you can search for all objects and their methods and usage in the dll project. If you know how to create an object of a classmodule, (if you don't look at HesaidJoes example with New keyword) you can create any public creatable class the same way.

[HeSaidJoe]

Shark:
When I created the dll I left the project name as Project1 so when I made the standard app, it has to have a different name. It could very well be V(ery)Basic or LOL or anything.

[kedaman]

Again, i may not be HeSaidJoe, but i think i could answer some of them anyway?

the exp and lib files are not nessesary, i'm not sure but they may be as oca files to ocx files, just info about the dll created.

No actual diffenrece between classes in activeX dll projects and standard exes, just that you can create public creatable or multiuse classmodules, but not private or public notcreatable, although you can refer to publicnotcreatable objects used by the dll, just like nodes object in treeview.

[parksie]

The .exp file contains a list of the DLL's exported functions/objects. The .lib file is only useful if you want to use compile-time dynamic linking with another language (ouch).