Visual Basic.NET for Mainframe Programmers

Visual Basic .NET for Mainframe Programmers

VBN‐001

Visual Basic .NET for Mainframe Programmers Getting Started with Visual Basic

Copyright © MindCross Training & Consulting ‐ All rights reserved. Page 2‐1

Getting Started with Visual Basic

This section will introduce you to some new terms and the Visual Studios Integrated Development

Environment (IDE). You will also learn how to develop and run projects.

Getting Started with Visual Basic Visual Basic .NET for Mainframe Programmers

Page 2‐2 Copyright © MindCross Training & Consulting ‐ All rights reserved.



Visual Basic IDE Overview

The Integrated Development Environment (IDE) The IDE in Visual Studios is comprised for four main areas. These are:

• Toolbox

• Properties

• Solution Explorer

• Tabbed work area

Modes of Operation

Within Visual Basic there are two modes of operation:

• Design mode – for developing applications • Runtime mode – for testing and running applications

When you initiate Visual Studios you will automatically be placed in design mode. When you debug or run a project you will be switched into runtime mode. Anytime you are in runtime mode you will see “Running” in the Visual Studios title bar.

The design area for an application is

a form



What is a Project? A Visual Basic Project is a container for all files and information about an application. The actual project file has an extension of .vbproj. All the files and information associated with a project can be found in the Solution Explorer window.

Different types of projects can be created within the IDE. The projects are created from project templates. Some of the ones you may use include:

• Windows application • Class library • Web control and Windows control library • ASP.NET Web application • ASP.NET Web service application

IDE Default Environment Settings

When you start working with the Visual Studios development environment a collection of settings will be available to you based on the environment settings defined. This can be specified the first time you start Visual Studios after installation or any time you begin working with Visual Studios. The three types of development activity from which you can choose include:

• General development • Visual Basic development • Web development

It’s important to have the appropriate one selected based on the work you will be doing. To specify the environment go to Tools >> Import and Export Settings. You can select to reset the settings, in which case you will be prompted with the development options, or you can import/export your preferred settings from a specified location. The settings environment settings will look similar to this:

Tour of the Integrated Development Environment

Projects as Containers

Import and Export Settings Wizard

A group of projects may be called a solution ‐ ‐

hence the term “Solution Explorer”



Designing Visual Basic Forms

ToolBox ‐ Controls To start designing forms in Visual Basic you will use the

Toolbox. By default the Toolbox is minimized, so the first thing you’ll want to do is change the display of the Toolbox.

• Place your cursor over the Toolbox icon.

• When the Toolbox is opened click the “Auto Hide” button in the top right corner.

The items in the toolbox are controls. These controls will be used to design the user interface. The controls are grouped into types. However, you can change the display based on your preferences.

Some of the common tools include:

• Button • CheckBox • Label • RadioButton • TextBox

The Format Menu

As your form is designed you will find it helpful to use the format menu for tasks such as aligning items, sizing, spacing, etc. Once your design is complete you may want to use “Lock Controls” to be sure your design doesn’t accidently change.

Tabbing Order When creating a form with user input items you’ll want to think about tabbing order ‐ ‐ the order in which the users will tab through the input fields.

Set the tabbing order by using the Tab Order function on the View menu. Once you are finished you can turn it off again.

How to: Resize controls

How to: Set the Tab Order

Windows Forms Controls by Function

• ComboBox • ProgressBar • PictureBox • ListBox • Panel



Properties As discussed in the section on “Object‐oriented Programming” properties are information or characteristics about something. For instance they maintain values about controls on your form.

The properties window displays the name of the item, or control, you’re working with, the inheritance information, along with a list of design time properties and their values. Some common properties we’ll be working with include:

• (Name) • Text • Font • BackColor • ForeColor • Enabled • Visible • Location

Each item, such as a control, form, or class, has a different set of properties associated with it. The properties listed are not a complete list of all properties available. The ones listed are the design properties ‐ ‐ meaning the properties you can change at design time. There are other properties that can only be changed programmatically. These changes would take place at runtime.

The Name property is unique. The Name property is the internal name of the form or control. You will use it any time you refer to that item within your program code; therefore, it’s important to have naming conventions and make it short, yet descriptive. It’s common practice to use a value that indicates the type of item.

Name property examples frmMain txtLastName



Creating a Project

The following steps will walk you through the process of creating a simple project. The project created will look similar to the window shown to the right.

1. File > New Project 2. Select the project type: Windows Application 3. Give it a name: Project1 4. Design the form using the Toolbox

• Add a panel control sizing it about the same size as the form

• Add two labels 5. Set the Text property for Label 1 to: Hello World! 6. Set the Text property for Label 2 to: Current date 7. Set the form properties

• Set the Text property to:My First Project Notice that the Text property changes the title bar

• Set the Backcolor property to any color of your choice 8. Add code to Form1_Load by double clicking on the title bar of your form in the design

panel. The code should be typed exactly as follows: Label2.Text = "Today is " & Now

Notes: Now is a system property of the DateTime object that holds the current date and time. The symbol & is used for concatenation.



Running and Saving a Project

1. Compile and run your project in one of the following ways

• F5 or Toolbar item: Start Debugging

• Menu: Debug >> Start Debugging 2. Set the location for where your project files should be saved

• Tools >> Options

• Click Project and Solutions

• For Visual Studios Projects Location browse and create the folders: My Documents\Visual Basic\Class\

• Click OK

3. Save all your project files

• File >> Save ALL

• Name: Project1

• Directory: Project1

A project file is a file containing pointers to other files. There are many file are associated with Visual Basic projects. Each file is considered a project item.

Note: The project files will be discussed later in the course.

More Details on the IDE

Visual Basic Menus

View Menu The view menu, for the most part, gives you a list of the available windows in Visual Basic. If you accidently close a window, or simply wish to view a particular window, you can invoke the View menu and select the window you want to view.

Object Browser One of the windows that we have not yet discussed is the Object Browser. The Object Browser is extremely useful, as it shows a complete list of components and system objects available to you and all the associated information for each object.

Since it’s sometimes hard to find exactly what you’re looking for a Search field is available to help you look for a particular object or object information.

Object Browser



The Object Browser window is broken down into four areas as follows.

For each object/component it shows the following information:

• Class name, and from where it is inherited

• Summary information

• Properties

• Methods

• Events

• Description and summary information

Project Menu The Project menu shows all the possible items that can be added to a project or solution. As more items are added they will be displayed in the Solution Explorer window.

Debug Menu The Debug menu is used to both run and test your project and to debug your project. The debugger is very user friendly and works similar to debugging utilities in other programming languages. For instance, to create a line break in your code you simply click on the line where you want the break to occur.

Tools Menu The main item to discuss in the Tools menu is the Options. The options item contains a lot of defaults for your development environment. In fact, there’s a section specific to just the Visual Basic environment called “VB Specifics”.

Walkthrough: Debugging a Windows Form

Environment, Options Dialog Box

Search

Object listing : : : :

Properties

Methods

Events

Description information

Members



Toolbox Window We already discussed the Toolbox; however, one problem using the Visual Studios Toolbox is the large number of tools from which to choose. Since it’s sometimes hard to find what you’re looking for keep in mind that the tools are, by default, listed in groups.

You can change the display of the Toolbox by clicking the bar specific to what you’re creating, for example, “All Windows Forms”.

Or, you can invoke the popup window with a Right Click and select “Sort Items Alphabetically”. This will change the display to sort all the tools in ascending order.

Solution Explorer Window The Solution Explorer window shows a complete listing of all files, items, and information associated with your project or solution. As you add new items using the Project menu they will appear in the Explorer window. From here you can also view the Project Properties by clicking “My Project”. These properties will be discussed later in the course.

Basic Coding Structures

Code Window Visual Basic code, like most other programming languages is very structured. The layout of all code modules is similar to what you see here.

The General Declarations section typically contains variables that will be shared throughout the module. That is an optional section. Below that is the definition of the class on which you are working with. This main section will be set up for you automatically by Visual Basic. Any code that you write will be contained within this section ‐ ‐ with the exception of general declarations.

Procedures are Blocks of Code Within the class start and end will be a series of procedures where all code will reside ‐ ‐ all code must be contained within some type of procedure block. There are a variety of different types of procedures in Visual Basic. Each will be discussed in detail throughout the course.

General Declarations Public Class . . .

Procedure : End Procedure : End . . .

End Class



For now, we’ll mention two common types of procedures:

• Sub Procedures • Function Procedures

Sub Procedures

Function Procedures

Handling Events Events are actions triggered by a state change or activity start of end. When events are triggered a block of code is executed and that block of code is a Sub Procedure which is responsible for handling the event process.

Each object, for example a button or textbox, has a set of events associated with it. The available events can be viewed from the Object Browser or code window.

: <modifier> Sub <procedure‐name> : End Sub

<modifier> Function <procedure‐name> (arg1, arg2, …) : End Function :

Sub procedures are a block of code which performs a task and does not return a value.

Function procedures are a block of code that does return one or more values.

Object List of events



Since an event code block is actually a Sub Procedure the syntax is the same. The syntax for an event should be similar to the following:

<modifier> Sub <object‐name_event‐name> . . . code

End Sub

Events Overview

Environment, Options Dialog Box

Mouse Events in Windows Forms

Setting Properties Programmatically During runtime of an application you can programmatically obtain the value of a property or set any modifiable property. The syntax to do this is fairly straight forward. Take a look at the examples below.

frmMain.Text = “Hello World!”

lblMsg = “Please try again”

Label2.Text = "Today is " & Now

Button1.Visible = False

When working in the Visual Basic code window, by default, you will see dynamic help which shows popup menus of information as you type your code. These dynamic windows can be extremely helpful as you learn Visual Basic.

Code Example

Private Sub Form1_FormClosing . . . MsgBox("Goodbye")

End Sub