Lab 14

 

  1. We have surveyed how to write form and code modules (with special attention to arrays and strings for storing data and to writing our own Sub and Function procedures to break code into small, focused pieces so that loop can be written compactly), we have reviewed the toolbox controls and become familiar with many of the events that the controls recognize and the process of coding event procedures. In this lab we turn to the organization of the GUI at run-time (forms and frames being the organizers at design time). We have built several forms for some of our projects, but we had to execute the forms one at a time by setting the project property to the form to be run when we ran the project. Thus our projects have utilized a SDI or single document interface. Chapter 11 introduces the MDI form that is visually distinctive from the forms we have been using in what two characteristics?

The child window, or MDI form, can never be moved outside of the parent window.  Also, the title bar, (1)icon, and name are different plus (2) the background color of the MDI is darker to indicate that it is a child window.
NOTEPAD AND FORMS
MDI can have multiple documents open at the same time.
The child window cannot be moved outside the parent.
The MDI form has a parent and a child window where a SDI form has only one window. With a MDI form you can have many windows open at once.
MDI can have multiple files open at the same time.

MDI applications have child and parent structure, with the parent window contain the child windows.

 

  1. A MDI form is added to a project from the Project menu. A project may have up to one MDI forms. ONE A project can only contain 1 MDI form. One one (1)_
  2. A "standard" form can be converted into a child form by changing the value of its MDIChild property. MDI MDIChild property to True MDIChild MDIChild
  3. Create a new project, add a second form, then add a MDI form. Run the project. What can the user do?  Render a window inside a window.
    THE USER CAN MINIMIZE THE FORMS WITHIN THE MDI ENVOIRMENT
    The user can move the child around in the MDI form, minimize, maximize and close the child window without closing the MDI form. When the user maximizes the form window the name of the form is placed in parenthesis on the MDI forms title bar. When the user closes the MDI form, the project stops running.
    The user can maximize or minimize the child form. The child form can be closed. The child form cannot be moved outside the parent window. When the parent is closed it closes the application, but when the child is closed it does not close the application.
    You can move the child window around in the MDIForm, minimize and maximize the child window, and close the child window.  The MDIForm will still be open after you close the child window, but when you close the MDIForm window, the project stops running.  When you maximize the child window, the title bar in the MDIForm changes to include the title of the child window.  You cannot move the child window outside the parent window.  When you try, the parent form (MDIForm) adds scroll bars.ßthe parent makes the area for the child BIGGER (inside the parent frame)  if you want to move the child past the current edge of the the parent.
  4. Check the startup object in the project properties and change it to a different form. What difference does it make? Different form loads and MDI form.  The title changes, etc.
    WHICH EVER FORM IS SELECTED TO BE EXECUTED THAT TITLE WOULD GO TO THE MDI’S TITLE BAR
    The difference changing the startup properties makes is which child form opens in the MDI form. If you have the MDI form selected to start, then a blank form opens with no child.
    When you set it to start up form 2 it makes no difference when it is set to startup the MDI form it opens with no child form.
    For example, if you have Form 1 selected, then when you run it, the MDIForm is parent, and the Form1 is opened within it.  If you have Form 2 selected, when you run it, the MDIForm is opened with Form2 inside of it.  On the other hand, when you have the MDIForm selected as the form to run, you get a blank MDIForm with no child window opened within it.
  5. Place some controls on each of your three forms. How are you restricted?  Controls without the align property cannot be added to MDI form.  In essence all controls except PictureBox can only be placed on the standard forms or child forms.
    THE REGULAR FORMS CAN HAVE BUTTONS, BUT THE MDI HAS TO HAVE CEARTAIN ALIGINMENTS. 
    There are only three controls that can be placed on the MDI form. These are the picture box, timer, and data controls. These controls are either not visible at run time or they contain the Align property. The other controls are restricted and an error message appears saying: Controls without the align property cannot be placed directly on the MDI form.
    You cannot place controls without the align property directly on the MDI form or controls not visible at run time.
    The MDI forms can only contain controls that have an align property (like PictureBox), or controls that are not visible at run-time (Timer control).  The only controls the MDI Form can contain  from the control bar allowed are:  data, picture and timer.
  6. What does the PictureBox offer in the way of removing the restriction?  The Picture Box allows you to place controls within its boundaries.  Basically, if you add a PictureBox to the MDI form you can then place your controls inside the PictureBox and thus on the MDI form.
    THE PICTURE BOX HAS ALIGINMENT PROPERTIES THAT TAKE AWAY THE RESTRICTIONS.
    The picture box allows the user to use it as a container and indirectly places the controls inside it.
     It can be used as a container to hold the controls that cannot be placed directly on the MDI parent form.      
         The PictureBox can be used as a “container,” which allows the programmer to indirectly use controls that are not allowed to be placed directly on the MDI parent form.
  7. Place a button in a picture box on the MDI form and then run with form1 as the start object. What do you observe about the behavior of form1?   Adjusts it size to fit in a newly defined area.  The PictureBox further limits the size that form1 can take on.
    IT CONTAINS THE PICTURE BOX AND DOES NOT MAXIMIZE TO FIT THE PARENT WINDOW.
    Form one is placed below the picturebox on the MDIform. The picturebox acts as a frame would on a web page. If you maximize the form1, it only maximizes to the bottom of the picturebox container and the MDI form takes the Form1 name into its title bar.
    It cannot cover the picture box on the MDI parent form.
    It is contained outside of the PictureBox in the MDI form.  It is resized to allow for the MDI control to be its full size.  The PictureBox acts in much the same way as a frame would on a web page.  When you maximize Form1, Form1 only maximizes to include the area not used by the PictureBox, and it changes the title bar property of the MDI form to include the name of Form1.
  8. Some form must be loaded first, and it can then load other forms. Place a button on each of your three forms. Label the button on Form1 "load form 2" . Label the button on the Midi form "load form 1". When either of these buttons are pressed, Call load for the specified form and then call that form’s show property. The button on Form2 should print on form1 "printing from form 2" every time it is pressed. Insert the project (*.vbp) file here.
    Type=Exe
    Form=Qst10b.frm
    Reference=*\G{00020430-0000-0000-C000
    000000000046}#2.0#0#C:\WINNT\System32\STDOLE2.TLB#OLE Automation
    Form=Qst10a.frm
    Form=Lab14.frm
    Startup="MDIForm1"
    HelpFile=""
    Command32=""
    Name="Project1"
    HelpContextID="0"
    CompatibleMode="0"
    MajorVer=1
    MinorVer=0
    RevisionVer=0
    AutoIncrementVer=0
    ServerSupportFiles=0
    VersionCompanyName="UALR"
    CompilationType=0
    OptimizationType=0
    FavorPentiumPro(tm)=0
    CodeViewDebugInfo=0
    NoAliasing=0
    BoundsCheck=0
    OverflowCheck=0
    FlPointCheck=0
    FDIVCheck=0
    UnroundedFP=0
    StartMode=0
    Unattended=0
    Retained=0
    ThreadPerObject=0
    MaxNumberOfThreads=1
  9. The Picture box is aligned top by default. Change its alignment to Right and run the project and observe what is different (record your observations here).   The PictueBox increased in size to fill the MDI window and would not allow for the loading of Form1 or Form2.  However, if you increase the size of the MDI, window before you run,  you can see that the PicturBox runs the length of the rightside of the MDI and the forms are loaded into the left column.  The major problem is getting the forms to fit within the windows.
    COMPARED TO TOP AND BOTTOM, THE LEFT ALIGIN PROPERTY FILLS THE WHOLE SCREEN.
    The picture box was on the far right side of the screen and when forms 1 and 2 were loaded, they became longer and skinner to load in the remaining part of the MDI form.
    Align right it takes up the whole right side.
    It aligns the PictureBox to the right, but it also makes it larger and increases the height from top of form to bottom.  It then loads forms to the left of it.  The forms are resized as well.  The width is decreased and the height is increased.

You cannot Print to the MDIform, but you CAN print to its picture box. Do so when form2’s button is pressed. MDIForm1.Picture1.Print  “printing from Form 2”
Private Sub Command1_Click()

MDIForm1.Picture1.Print "Printing from form 2"
End Sub
MDIForm1.Picture1.Print "printing from form 2"
Private Sub Command1_Click()

    MDIForm1.Picture1.Print "Printing from Form 2"
End Sub

 

  1. Add two buttons to the MDIform, one labeled Tile and the the other labeled Cascade. When either is pressed, invoke the Arrange method with the proper argument and explain what happens here.

Cascade layers the forms while Tile fills the area of the MDI form with how many ever forms you have.  You can either use tile horizonal(1) or tile vertical(2).
THE WINDOWS BECOME ARRANGED IN AN ORDER, BUT WHEN TILE IS PRESSED THE WINDOWS LINE UP VERTICALLY.
After the forms are loaded, when you press tile, form1 and form2 are placed in the empty space on the MDI form. Form 1 above form 2. They are the same size and shape. When you press cascade, the forms are placed with form2 a little below form1, but on top of it.
The cascade button stacks the windows on top of each other and the tile button fills up the form with the 2 windows next to each other.
When the Tile button is pressed, it fills up the area equally with form 1 and 2.  In other words, they are “tiled.”  On the other hand, when Cascade is pressed, it cascades the windows on top of each other, aligning them so that you can see each one’s form title bar.

12.     Modify the project to that the button to load a form also unloads the other other form. Insert the *.frm file for form2 here.

Option Explicit
Private Sub Command1_Click()
Call Load(Form2)
Call Unload(Form1)
Call Form2.Show
End Sub
You had TWO load buttons, one for form1 and one for form2.  This is the form2 button altered correctly.
VERSION 5.00

Begin VB.MDIForm MDIForm1 ßbutton loads form1 inside PictureBox

   BackColor       =   &H8000000C&

   Caption         =   "MDIForm1"

   ClientHeight    =   8025

   ClientLeft      =   45

   ClientTop       =   270

   ClientWidth     =   7935

   LinkTopic       =   "MDIForm1"

   StartUpPosition =   3  'Windows Default

   Begin VB.PictureBox Picture1 ß PictureBox defined

      Align           =   1  'Align Top

      Height          =   1215

      Left            =   0

      ScaleHeight     =   1155

      ScaleWidth      =   7875

      TabIndex        =   0

      Top             =   0

      Width           =   7935

      Begin VB.CommandButton Command3 ß wanted “Load form”

         Caption         =   "UNLOAD FORM"

         Height          =   615

         Left            =   360

         TabIndex        =   3

         Top             =   480

         Width           =   2175

      End

      Begin VB.CommandButton Command2

         Caption         =   "TILE"

         Height          =   615

         Left            =   5160

         TabIndex        =   2

         Top             =   480

         Width           =   2415

      End

      Begin VB.CommandButton Command1

         Caption         =   "CASCADE"

         Height          =   615

         Left            =   2640

         TabIndex        =   1

         Top             =   480

         Width           =   2295

      End Button

   End PictureBox

End MDIform1

Attribute VB_Name = "MDIForm1"

Attribute VB_GlobalNameSpace = False

Attribute VB_Creatable = False

Attribute VB_PredeclaredId = True

Attribute VB_Exposed = False

Private Sub Command1_Click()

Arrange (0)     ßCascade

End Sub

 

Private Sub Command2_Click()

Arrange (1)  ßTile

End Sub

 

Private Sub Command3_Click()

Call load(Form1)

Call Unload(Form2)
Form1.show

End Sub

  1. MDI forms serve as a frame to hold multiple windows and its Arrange method determines how the child windows appear in the frame. The MDIframe may also contain other controls (we could have a second PictureBox). However, we can have multiple forms displayed on the screen without nesting them insider a MDIform. Add a third form to the project and use the Form Layout window to position it in the upper right corner while the MDIform1 is positioned with its upper left corner toward the middle of the screen. Place a button on form3 the loads and shows the MDIform and set form3 as the load object. Manipulate both forms to the extent that you can and then explain how form3 and the MDIform interact when the project is run.

As long as you use the Call ___.Show, the MDI form will appear wherever you have told the layout to load it to.  However, you cannot set the positioning for the forms that render in the MDI window.  The user is only allowed to manipulate the external forms, i.e. standard forms and MDI forms.
FORM THREE CALLS THE MDI FORM TO BE PROMPTED BUT BOTH ARE IN DIFFERENT POSITIONS. SO FORM 3 DOES NOT GO ON TO MDI FORM.
When the project runs, form 3 is displayed in the Right hand corner. You click on the button on from 3 and the MDI form is displayed in the Left hand corner. They interact separately. You can click and drag each, and which ever one you click on has the focus. The project does not end until you close BOTH windows.
When the load form 3 button is pressed it puts the focus on form 3 and when the button is pressed to load the MDI form the focus changes to the MDI form.
When the project is run, form3 appears in the upper righthand corner.  When you press its button, the MDIForm appears in the middle of the screen.  Both the MDIForm and Form3 are shown running in the bottom task bar, and each can be minimized, maximized or closed separately.  If you maximize the windows, whichever form has the focus is the one brought to the front.  You can resize the boxes separately and click on either to obtain focus.  You can also click and drag the forms over each other, with the one you are dragging remaining on top, since it has the focus.

  1. The remaining entry on the project properties start object drop-down is Sub Main. This procedure must be written and stored in a *.bas module because it is NOT connected to a form. It is explained on page 472 and illustarted on page 473. How is it like and unlike a form_Load event procedure ?  The form_Load is used to load information automatically to a form when the form is activated.  However, when many forms are used, the Sub Main is used to make sure that VB starts with the correct form.  Thus, the form_Load is used to “upload” information to a form, while Sub Main is used to load the proper forms in the proper order, so to speak.
    IT IS LIKE A PROCEDURE BY USING ARGUMENTS, BUT DOES NOT NEED AN TERMINATION.
    There is not a GUI in the sub main. Any code in the *.bas associated with the sub main would be executed prior  to any GUI loading.
    With the Main Procedure does not have to have a GUI associated with it runs independent of the GUI and can start up many forms on run. It is the same in respect that the form is loaded into memory and is called to use.
    The main procedure has no GUI associated with it.  Any code associated with the main procedure would be executed prior to any GUI loading.
  2. Forms have a title and we have exercised the minimize and maximize buttons at the right end of the title bar, but we have only used the close button to end the program. In 14 we should have noticed that the close button only ended the program because there was no other form being displayed. The event procedure QueryUnload is called when the close button is pressed, and if no code has been provided, the form Unload event is processed. Pages 472 to 475 illustrate writing code for the QueryUnload, code which uses the MsgBox with a Yes/No option. The example deals with four different frames. How many are visible at once? For each visible frame, what happens when its close button is pressed (you may have to run the author’s code to find the answer, but if so, you want to either remark out the set statements in frmStarter or find the path to the *.gif files )?  Only one form is visible at a time and each time any of the close buttons are hit, a ß not so.   There are 4 forms and two are visible at a time.   MsgBox appears that asks if you are sure you want to exit and returns a 0 or 1 depending on whether you select Yes or No.
    YOU ARE ASKED BY THE COMPLIER IF YOU WOULD LIKE TO SAVE CHANGES OR EXIT THE PROGRAM.
    Only one frame is visible at a time. You must close the picture form, before you can click on the Starter form and try to open another picture form. When you close the picture forms, it brings the focus back to the Starter form. When you close the Starter form, it displays a message asking if you are sure you want to close.
    Only one is visible at a time. When the close button is pressed you can the close the MDI form and it asks if you are sure you want to exit. The frame just closes when its close button is pressed.
    One frame is visible at a time.   When you close the individual frames, they just close, but when you try to close the frame with the 3 buttons on it, it asks you if you are sure you want to exit and yes or no. 
  3. Explain why the author used an array of images in fir. 11.16. Would the program work the same if all of the buttons said
    frmForm1.imageImage.Picture=….
    Call frmForm1.Show(….
    That is, if ONLY ONE FRAME WERE USED?  Yes, all the array values are defined and then there are no step throughs in any of the code.  Therefore, the author only needs to indicate the name of the value he wants placed where.   
    ONLY ONE FRAME WERE USED? I DON’T THINK IT WOULD WORK BECAUSE YOU ONLY HAVE ONE FRAME, AND TO USE THE CALL FRM METHOD WOULD WORK, BUT IF YOU HAVE ONLY ONE FRAME WHY USE IT. ßbut frames only differ by the picture you load into them!
    He used an array to hold the different pictures, however, he could do this using one form. The title bar is the only thing that would be affected. It would display form1, unless the buttons were coded to change the title in the title bar.
    The array holds the 3 different pictures but the author did not need to use three different forms to display the pictures. But yes it will work either way.
    He used an array to hold the different pictures, but you could do it all using one form.  The title bar on the form would have to be changed each time.
  4. When Windows Explorer is used to click on a *.frm file VB60 is called and the form file is added to a default project and executed. However, VB60 can be set to make an *.exe file that will execute in Windows without VB (except that it may still need the *.dll file). This is discussed in 11.10, EXCEPT that your demo version of VB60 does not have this capability. Write and execute the program specified in exercise 11.10. Although this is just a "busy" loop and it is not expecting the user to do anything else, if it takes a long time we might get tired and like to stop (there should be a start and stop button on the interface and a textbox into which the 200 million or some like number can be input before the START button is pressed, and there should be a label in which the elapse time is displayed). Therefore you will want to use the DoEvents method as illustrated in fig. 11.20 and discussed on p. 479. 

Option Explicit
Private Sub Command1_Click()
Dim x As Long, Time As Long, Counter As Long
 
Time = Timer()ßa function like NOW that returns the clock value
For x = 200000000 To 0 Step –1
  Text1.Text = x
  DoEventsßwithout this the Stop button won’t work
Next x
Counter = Timer() – Time
Label1.Caption = Counter
End Sub

Private Sub Command2_Click()
End
End Sub