Writing Visual Basic Instructions

The final type of window discussed here is the Code window.  To open the Code window for a form, click the Project Explorer and click View Code, or choose View, Code.  This opens the window shown in Figure 2.7.  The object shown is the Form; the procedure is shown as Load().  The title bar reads Form1 because you have not changed the name of the form.

Figure 2.7 This Code window shows the start of a Form_Load() procedure.

The Code window contains the first two coded instructions, which are entered for you.  The first combines the name of the object with the name of the event procedure.  This coded instruction is shown in the following example, in which Load() is a special type of event:

Private Sub Form_Load()

It occurs when a form is first loaded.  However, suppose you want to change the event from Load() to Click().  By selecting Click (click the procedure list box and scroll to Click, as shown in Figure 2.8), the first coded instruction changes to the following, in which Click() is another type of event:

Private Sub Form_click()

It is triggered by a mouse click.

Figure 2.8 The Code window now shows the start of a Form_click() procedure.

The event has now been changed from occurring at the time the form is loaded to the time when the form is clicked, with the user controlling the time of the event with the click of the mouse.

The ending instruction stays the same.  It reads as follows, which means the end of the procedure (sub):

End Sub

Exercise 2.4  Adding a Click() Procedure

In this exercise, you begin a new project.

1. Choose File, New Project and open a Standard EXE project.  If the last project is still on-screen and has not been saved, you will be asked if you want to save changes to P2-3.vbp? Click No, unless you have already saved it.  Either way will not lead to problems.
2. When Form1 appears, double-click to open the Code window.
3. Change the Project name to Project2_4.
4. Change the procedure name from Form() to Click() in the procedure list box.

   Your code should read as follows:

   Private Sub Form_Click()
   End Sub
   

5. Type the following to create the procedure:

   Private Sub Form_Click()
   'This procedure will display a message on the form
   Print
   Print
   Print "When you click, look at what happens!"
   End Sub

6. Close the Code window by double-clicking the Control box icon.
7. Choose Run,Start;click the Start icon on the toolbar; or press F5 to run your procedure. When Form1 appears, place the mouse pointer on the form and click. What happens?
8. Click the form again. What happens? It makes you want to click forever doesn't it?
9. Choose Run, End from the menu bar or press the End button on the toolbar to return to the design of Form1.
10. Save this form and project. You can call the Form F2-4.frm and the project P2-4.vbp if you want to use them in later exercises; however this is not necessary. Continue with the next exercise using the same form.

Exercise 2.5 Adding a KeyPress() Procedure

In this exercise you add a second procedure to a form. Figure 2.9 shows the revised form. This exercise assumes you have completed Exercise 2.4 and are using that form.

Figure 2.9

Adding a KeyPress() procedure to the form places more than one procedure on the same form.

1. Choose View, Code from the menu bar. The code you wrote for Exercise 2.4 should appear.
2. Choose KeyPress from the Procedure list box, and observe what happens to your code.
3. type the following to complete this procedure:

   Private Sub Form_KeyPress (KeyAscii as Integer)
   'This procedure will display a different message on the screen
   Print
   Print
   Print "    When you press a key, look at what happens!"
   End Sub

4. Close this procedure (using the Control menu icon) and run the revised program. There are four ways to run your program:
   • Choose Run, Start.
   • Choose Run, Start with Full Compile.
   • Press F5.
   • Press the Start button on the toolbar.

   This time, press F5 to start your program; then as a test, do the following:

   1. Click the form.
   2. Press a key.
   3. Press a second key.
5. Click the End button on the toolbar to stop your program a different way, or choose Run, End to stop the program.
6. When you are returned to Form1, double-click the form to open the Code window. What code appears?
7. Scroll through the list of procedures in the Procedure menu. Coded procedures are displayed in bold.
8. Save this form and project at this time. You will be asked to work with the form and project in the next several exercises, but it is wise to save your work periodically. You can save your form as F2-5.frm and your project as P2-5.vbp to keep your examples in sequence. Name the project Project2_5 before saving.

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Disabling the Minimize Button

With the first two border styles, the Minimize button appears unless it is disabled by the Minbutton property to change the setting to False.  (With this property, there are only two choices: True and False.)

Disabling the Maximize Button

With the first two borderstyles, the Maximize button appears, unless it is disabled.  To disable the button, double-click the MaxButton property to change the setting to False. (Like MinButton, only two choices are available with MaxButton: True and False.)

Disabling the Control Box

With the first three border styles, the control box appears unless it is disabled.  To disable the box, double-click the ControlBox property to change the setting to False. (The two settings for ControlBox are True and False.)

Changing the Window State

The WindowState property determines the appearance of the form at runtime.  Table 2.3 shows its three settings.

Table 2.3 The Settings for the WindowState Property

Value	Setting	Description
0	Normal	The form appears in normal size (the default).
1	Minimized	The form is minimized and appears as an icon (either on the taskbar or above it) when the application is run.
2	Maximized	The form is maximized and expands to fit the entire screen when the application is run.

Changing the background Color

Part of the enjoyment of working with Visual Basic is the ease with which colors can be added to a form.  Color settings are expressed in hexadecimal notation (base 16). The designers of Visual Basic did not expect you to work with hexadecimal numbers and instead provided a color palette.  To open the palette, double-click the Backcolor setting and click Palette.  When the Color palette appears, click a color to change the background color of the form.  Following the click, the hexadecimal number assigned to the color appears in the text box.

Changing Font Properties

When working with text, Visual Basic enables you to change the font (or text style) you are working with.  To determine which fonts are available on your system, open the Properties window, highlight Font, and click the ellipsis button to the right.  A dialog box appears for setting numerous font properties, including Name, Bold, Italic, Size, StrikeThrough, and Underline.

Changing the Foreground Color

The ForeColor property determines the color of the text and graphics to be displayed.  This differs from Backcolor, which determines the background color of the object.  To set this property, double-click ForeColor and click Palette.  Make the color selection using the palette.

Changing the Startup Position

The StartUpPosition property specifies the position of the form when it first appears.  Table 2.4 shows its four settings.

Table 2.4 The Settings of the StartUpPosition Property

Constant	Value	Description
vbStartUpManual	0	No initial setting specified
vbStartUpOwner	1	Center on the item to which the UserForm belongs.
vbStartUpScreen	2	Center on the whole screen.
vbStartUpWindows	3	Position in upper-left corner of screen.

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Opening the Properties Window and Changing Form Properties

Besides a Project Explorer window, each form (or control) contains a Properties window.  As stated in Running a Visual Basic Program, a property is a named attribute of an object.  Properties are used to change the appearance or behavior of objects.

Figure 2.6 illustrates the default Properties dialog box for a form.  If this box is not visible, you can bring it into view by pressing the F4 function key, or choosing View, Properties Window.  With the form having the focus, press your right mouse button and drag down the Properties list.

Figure 2.6
The Properties dialog box of a form contains the built-in form attributes that you can change.

Over 50 properties can be set for a form.  Although this number seems overwhelming at first, some properties are used so frequently that they represent an initial set to remember.

Form Properties

Caption Name BorderStyle MinButton MaxButton ControlBox WindowSize BackColor

FontName FontSize FontBold FontItalic FontStrikethru FontUnderline ForeColor StartUpPosition

To simplify this list somewhat, the items can be grouped by their uses:

• Seven properties deal with the way in which the form or text appears on the display screen (Caption, BorderStyle, MinButton, MaxButton, ControlBox, WindowSize and StartUpPosition).
• The identification of an object is specified by the Name property.
• Font settings are controlled using the Fonts dialog box (FontName, FontSize, FontBold, FontItalic and FontStrikethru).
• Color settings (ForeColor and BackColor) use a special palette.

There are three ways to change most property settings:

• Click the property to highlight it, and enter (type in text) the new property setting in the text box.
• Double-click the setting to view the alternative settings.
• Click the down arrow to open the drop-down menu for property settings.

Properties for fonts and color launch a separate dialog box for you to enter settings.

Changing a Caption

The Caption property enables you to change the title that appears on the top of a form.  Instead of Form1, use the Caption property to add a title.  To change the caption, select Caption in the Properties dialog box and type the new title in the text box next to the property name.

Changing a Form Name

The Name property specifies the name of the form to be used in writing Visual Basic code. Remember the following rule: The name, not the caption, is the identifier.  When writing coded instructions, the Name property appears as the object name.  To change the name, select Name in the Properties dialog box and type the new name.

Changing the Border Style

The BorderStyle property enables you to change the appearance of the form’s border.  To change the border setting, double-click the current setting to reveal other choices, or click the down arrow to open the drop-down list of the six options.

If you are uncertain about the six border choices and their precise effects, click BorderStyle to give it the focus in the Properties dialog box, and press F1 (the Help function key).  Visual Basic Help displays the six style choices and explains their effects, as shown in Table 2.2.

Table 2.2 The Settings for the BorderStyle Property

Setting	Style	Description
0	None	No border or border-related elements.
1	Fixed Single	Can include Control menu icon, title bar, Maximize button, and Minimize button.  Resizable only using Maximize and Minimize buttons.
2	Sizable	The default.  The size can be changed using any of the optional border elements listed for setting 1.
3	Fixed Dialog	Can include Control menu icon and title bar; can’t include Maxiimize or Minimize buttons.  Not resizable.
4	FixedToolWindow	Under 16-bit versions of Windows and Windows NT 3.51 and earlier, behaves like Fixed Single.  Does not display Maximize or Minimize buttons.  Not resizable.  Under Windows 95, displays the Close button and displays the title bar text in a reduced font size.  The form does not appear in the Windows 95 taskbar.
5	SizableToolWindow	Under 16-bit version of Windows and Windows NT 3.5 and earlier, behaves like sizable.  Docs not display Maximize or Minimize buttons, Resizable.  Under Windows 95, displays the Close button and displays the title bar text in a reduced font size.  The form does not appear in the Windows 95 taskbar.

The online Help is one of Visual Basic’s strongest features.  Remember, the F1 key is your friend!  Use it often.  The language is just too vast to remember all of it.

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The concept of Focus

The concept of focus is important in Visual Basic.  The object that is selected (such as a form, control, or menu bar selection) is said to have focus.  In order for Visual Basic to know what file to save, it is necessary to click the object to give it focus, making it the active object.  Likewise, to remove a file, the object must be given focus.  To remove a file, open the Project window, click the file to remove, and choose File, Remove and the name of the file to remove will also appear.  An alternative is to display the Project Explorer, click the file that you want to delete, and right-click to produce the shortcut menu shown in Figure 2.3.  We discuss the concept of focus at length later.  There are even unique events, such as Gotfocus and LostFocus, that deal with this issue.

Figure 2.3 Display the Project Explorer and right-click to reveal several file optiions, including a command for removing a file from a project.

Exercise 2.2  Using the Remove and Add Commands

This exercise assumes that you completed Exercise 2.1 and saved the form as F2-1.frm.

1. Open a new Standard EXE project, and change the name of the project to Project2_2 (click Project, Project1 Properties).
2. Choose Project, Remove Form1.Form1 must have the focus because it is the only object assigned to the project.
3. Choose Project, Add File.  Navigate through Windows to the location where you saved F2-1.frm, and add this form to your Project (see Figure 2.4).
   

   Figure 2.4

   The Add File dialog box lists saved forms that can be added to a project.

4. Open the Project Explorer Window, and give form F2-1.frm the focus.
5. Choose File, Save File As (or click the right mouse button).  When the dialog box opens, navigate to the location where you want to save the file, and name it F2-2.frm.
6. Open the Project Window again and observe what happens.  The name of the form has been changed and assigned to the new project.
7. Choose File, Save Project As.  In this instance, you are not asked to name the form because it has already been named and saved.  Instead, you are asked only to name the project, which we named P2-2.vbp.

Other File Menu Commands

Besides the four Project menu commands and the two file commands found on the File menu, the latter also contains the Print and Print Setup commands and the Make Project1.Exe commands, as follows:

• Print – Choose File, Print to display several options for printing information about a project (see Figure 2.5).  You can print the form image, code, or the form as text, and you can choose to print information for a module or for the entire project.
• Print Setup – Choose File, Print Setup to launch the standard Windows Print Setup dialog box.
• Make Project1.Exe – Choose File, Make Project.Exe to create an executable application.  Project modules are compiled into a single .EXE file.  This file is either a P-Code interpreted executable or a native code executable file.  (The two code formats are explained in “Interpreted P-Code,” and “Compiled Native Code,” later.)

Both types of executables require runtime files.  The Visual Basic Setup Wizard can help you determine which runtime file your application requires.

Figure 2.5 The Print-Project dialog box enables you to choose the parts of an application that you want to print.

Exercise 2.3  Using the Print Command

This exercise is designed to show you the type of information printed for a project.

1. Open a new Standard EXE project.
2. Choose File, Print.
3. When the dialog box appears, click Current Project, Form Image, Code and Form as Text.
4. Click OK.

What is the difference between the Form Image and the Form as Text choice!  Why is there no computer code?

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Naming a Project

Each time you begin a new project, the default name, Project1, appears at top of the form.  Unless you change the name, every project you work on will be named Project1.  To change the name, choose Project, Project1 Properties (see Figure 2.2), and type a new project name.  For example, you might enter Project2_1 for this initial project.

Figure 2.2 The Project Properties dialog box is used to change the name of the project from the default, Project1, to a name of your choosing.

Exercise 2.1 Using the Save Project As Command

This exercise asks you to do very little, but it does introduce you to the file naming conventions. Start Visual Basic, and perform the following steps:

1. Open a Standard EXE new project.
2. Choose Project, Project1 Properties and change the name of the project to Project2_1. Click OK. This new name should appear on the topmost title bar of Visual Basic.
3. Choose File, Save Project As. A dialog box appears and asks if you want to save the file as Form1.frm. If you click Cancel, the form is not saved and you have to rebuild it if you need it. Imagine that you spent an hour perfecting a form. Unless you save it, your work will be lost.
4. Before you click Save, navigate to the location where you want to save the file, and assign a name to the form. Assign a unique name - something other than the default, Form1.frm. You can use the notation F2-1.frm to indicate that this form goes with exercise 2.1 (not very clever, but it works). A more descriptive name would be better.

   If you want to store the form on a diskette placed in the a: drive of the computer, navigate to the drive and type F2-1.frm.

5. After the form has been saved, a second dialog box appears asking you to assign a name to the project. Again, assign a unique name (not the default, Project1.VBP). You can call it P2-1.VBP to indicate that this project goes with Exercise 2.1. Here too, a descriptive project name would be better.

If you want to save the project on a diskette placed in the a: drive of the computer, navigate to the drive and type P2-1.VBP

The Add File and Remove File Commands

Files can be added to, or removed from, the .VBP project file using the file commands contained on the Project menu. When adding or removing files, keep in mind that you are adding or removing files from a project. The following are two Project menu commands that you will use often in this book:

• Add File - Choose Project, Add File to open a dialog box (see Figure 2.4) that enables you to navigate the Windows file directory to identify a previously saved file and to add the file to a project, for example, an .FRM (form), .BAS (coded module), .CLS (class modules), or .RES (resource file). This command is especially important when you use a file built for a different project. Simply identify the file name, and click OK.
• Remove <Name of File> - Choose Project, Remove <Name of File> to remove the file from the current Project that is active (has the focus, a term that is described next).

Other Project menu file commands include Add Form, Add MDI Form, Add Module, and Add Class Module. These enable you to add new types of forms and modules to a project.

The Save File and Save File As Commands

The following are two File menu commands that are used to save a particular file rather than an entire project:

• Save File - Choose File, Save File to save the form or module that is active (has the focus). If the file has previously been saved, this command updates the file. If the file is new, this command prompts you for the name of the file and, once entered, adds the file to a project when the project file (.VBP file) is next saved.
• Save File As - Choose File, Save File As to save the current file to a disk. This option always prompts you for the file name. Like the File, Save Project As command, File, Save File As is used to save a file for the first time or to save a copy of an existing file.

You will find file commands most useful when you want to use the same forms and modules in different projects.  There is nothing to prohibit you from using the same form in dozens of projects because each form is saved as a separate file.

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Learning How to Manage Visual Basic Projects

In this section, you learn how to open and save a project, add and delete files from the Project window, give an object focus (further explained in later section “The Concept of Focus”), and use the other File commands provided with Visual Basic.  You will also work through several exercises to rest your knowledge of the concepts presented.

Opening, Saving, Adding and Removing Projects

Whenever you open Visual Basic, you always start a new project.  However, there are File commands that enable you to work with both old and new projects, and File and Project commands for working with old and new files.  The File menu on the menu bar contains six commands designed for managing projects, as follows:

• New Projects – Choose File, New Project to start a new project.  If you are working on a project, this command prompts you to save the current project.  It then closes the current project to enable you to start a new one.
• Open Project -  Choose File, Open Project to open a saved project.  Before opening a project, this command asks if you want to save a current project if one exists.
• Add Project – Choose File, Add Project to open a saved project and add it to another, provided one exists.  A Visual Basic application can contain any number of projects.
• Remove Project – Choose File, Remove Project to remove the selected project from a project group.
• Save Project As – Choose File, Save Project As to save the current project to a disk.  This option always prompts you for a project name.  Use this command to save a project for the first time or save a copy of an existing project.  When first saving a project, you are asked whether or not you want to save each form and module associated with a project.

  For each form or module, you can assign a name.  You should name each form with a name other than the default name (such as form1.frm and form2.frm); otherwise, you will design over the form when you start a new project and find it impossible to retrieve the form you thought you had saved.  You should also name each project with a unique name, or else Visual Basic will assign every project the same default name.

• Save Project – Choose File, Save Project to save the current project to a disk.  this option saves all forms and modules as separate files.  It creates a file with .VBP (Visual Basic Project) extension.  If the project is being saved for the first time, this command prompts you for the project name.  If saved earlier, it updates the .VBP file.

The .VBP file is saved as text or in ANSI (American National Standards Institute) format.  This allows you to inspect its contents with any text editor.  Each project contains one – and only one - .VBP file, which provides a description of the project, showing the names of the stored files and other descriptive information.

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Understanding the Concept of a Visual Basic Project

Every Visual Basic application is defined and saved as a project.  Each project, in turn, consists of a collection of files.  These files can include modules, insertable objects, and a single resource file.  Projects themselves are tracked by a project file, which has a .VBP extension.

Form modules, as discussed earlier are first seen as a windows with a caption, but little else.  From modules contain coded instructions called procedures for the form itself and for the controls and insertable objects placed on the form.  Other modules include standard modules and class modules.  You will learn the differences among these types of modules as you progress.

The tools of the toolbox represent controls and insertable objects.  The toolbox can be made visible or invisible by choosing View, Toolbox.  When visible, the toolbox contains a set of icons – each representing a standard or a custom control.  A Visual Basic project always includes a set of standard controls and can also include custom controls.  Each custom control has an .OCX extension.  In this section you are asked to write some beginning Visual Baisc procedures for forms.  In “Adding Controls and Event Procedures to Form Modules,” you will add procedures for stand controls.

Projects can also include a resource file, which can contain either binary data, such as images and sounds, or string data.  Resource files need to be created by a Windows resource compiler (typically a C or C++ language compiler), or you can use the resource compiler bundled with Visual Basic.

The Files that Make Up a Stanbdard EXE Project

In working with Visual Basic, you are asked to work with different types of files.  Each file type is given a unique file extension, which enables you to identify it.  Visual Basic contains over two dozen types of files, each of which has a different extension.  The Table below shows eight common file types contained within a project, their extensions, and their meanings.

Table 2.1 Common File Types

Type of File	Extension	Extension
Standard Module	.BAS	Each coded module is saved as a file
Class Module	.CLS	Each class module is saved as a file
Form Module	.FRM	Each form is saved as a file
Binary	.FRX	Each Icon or Picture property value is saved by Visual Basic in .FRX form
Log	.LOG	A file for logging load errors.
Resource	.RES	A project can have a single resource file for storing binary and string data
Project	.VBP	Each project is saved as a file.
Workspace	.VBW	Each workspace for a project is saved as a file.

This file notation is used throughout.  When you save a form, it is saved with a .FRM extension, and all event procedures written for that form are also saved in the .FRM file.  Because procedures are not saved as separate files with their own unique extension, they become bound to forms.  When you write and save a coded standard module, it is saved with a .BAS extension.  Coded modules are thus different from event procedures written for forms.  Coded modules are not bound to forms.

The Project Window (Project Explorer) in the Visual Basic Design Environment

Whenever you begin a Visual Basic program, you begin a new project.  Each project can contain several forms, several standard and class coded modules, and custom controls.  The Project window displays a list of all modules assigned to a project.  Whenever you begin a new project, a default Project window is created (see Fiigure 2.1) .  If the window fails to appear or is hidden, choose View, Project Explorer; press Ctrl+R; or click the Project Explorer icon.  In addition, your environment can be set to remove the docking of the Project Explorer.  This setting is controlled by choosing Tools, Options, clicking the Docking tab, and turning off the Project Explorer and Object browser selections.

Figure 2.1: This Project window reveals that Project1 contains a forms folder that is limited to a single form.

Figure 2.1 illustrates a Project window that contains three small icons on the left-hand side.  The leftmost icon enables you to view code, while the middle one enables you to view the underlying object (which in this case is the form).  Forms, the third icon, is important when projects become large and contain several forms or when projects are combined.  With large projects, all forms are placed in one folder, and all modules are placed in a second.  Toggling forms enables you to show or hide all forms for a project that are contained in the Forms folder.

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