CIS 115 Lecture 2

 Visual Studio 2005 Professional Edition (Requires Windows XP Pro)  MSDN Library for Visual Studio 2005 Available from MSDNAA

  A platform that allows the development and deployment of desktop and web applications Allows user choice of many .NET languages  May program in One of them  ▪ ▪ May create different parts of application in different languages ▪ Visual Basic ▪ C# (C Sharp) C++ J++ ▪ Etc.

 Integrated Development Environment – allows the automation of many of the common programming tasks in one environment  Writing the code  Checking for Syntax (Language) errors  Compiling and Interpreting(Transferring to computer language)  Debugging (Fixing Run-time or Logic Errors)  Running the Application

    4th Generation Programming Environment / Development Language Based on BASIC language  Beginners All-Purpose Symbolic Instructional Code Most widely used tool for developing Windows Applications  Graphical User Interface (GUI)  Menus, Buttons, Icons to help the user Full Object-Oriented Programming Language

Visual Studio .NET

Integrated Development Environment Visual Basic compiler .NET Framework Common Language Runtime 1 Solution Project

Source files

2 Assembly

Intermediate Language (IL) Class references

3

   User creates a new project in Visual Studio  A solution and a folder are created at the same time with the same name as the project  The project belongs to the solution  Multiple projects can be included in a solution Solution  Contains several folders that define an application’s structure  Solution files have a file suffix of .sln

Project: contains files for a part of the solution  Project file is used to create an executable application  A project file has a suffix of .vbproj

 Every project has a type (Console, Windows, etc.)  Every project has an entry point: A Sub procedure named Main or a Form

 Solution folder  Solution file (.sln)  Project folder ▪ Project file (.vbproj) ▪ Visual Basic source files (.vb) ▪ My Project folder: contains configuration information common to all projects ▪ The file AssemblyInfo.vb contains assembly metadata ▪ The References folder contains references to other assemblies ▪ The bin folder contains the executable file produced as a result of compiling the application

 Select the “Create Project” option from the “Recent Projects” box on the Start Page

   This is a Visual Basic GUI object called a form Forms are the windows and dialog boxes that display when a program runs.

A form is an object that contains other objects such as buttons, text boxes, and labels

     Form elements are objects called

controls

This form has:  Two

TextBox

controls  Four

Label

controls  Two

Button

controls The value displayed by a control is held in the

text property

of the control Left button text property is Calculate Gross Pay Buttons have methods attached to

events

T o o l b o x Design Window Properties Window Solution Explorer

 Step 1: Add a Control to the Form – Button  Look in the Toolbox for the Button Control  Select the Button with the Mouse  Draw a Rectangle Region in the Design Window by holding the mouse button down  Release the mouse button to see your button  (Can also be added by double clicking on the button in the Toolbox)

  Add a Second Button to the Form Put it in the lower right corner    The project now contains a form with 2 button controls

 Properties  All controls have properties   Each property has a value (or values)  Determine the Look and Feel (and sometimes behavior) of a Control  Set initially through the Properties Window Properties Set for this Application  Name  Text

     The name property establishes a means for the program to refer to that control Controls are assigned relatively meaningless names when created Change these names to something more meaningful Control names must start with a letter Remaining characters may be letters, digits, or underscore

 The label controls use the default names (Label1, etc.)  Text boxes, buttons, and the Gross Pay label play an active role in the program and have been changed Label1 Label2 Label3 txtHoursWorked txtPayRate lblGrossPay btnCalcGrossPay btnClose

  Should be meaningful 1st 3 lowercase letters indicate the type of control  txt… for Text Boxes  lbl… for Labels     btn… for Buttons After that, capitalize the first letter of each word txtHoursWorked is clearer than txthoursworked Change the name property  Set the name of button1 to btnWelcome  Set the name of button2 to btnExit

  Click on the Control in the Design Window Select the appropriate property in the Properties Window

  Determines the visible text on the control Change the text property   bntWelcome  set to “Say Welcome” btnExit  set to “Exit”  Do not need to include the “ “ in your text field  Notice how the buttons now display the new text

  The GUI environment is

event-driven

An event is an action that takes place within a program  Clicking a button (a Click event)    Keying in a TextBox (a TextChanged event) Visual Basic controls are capable of detecting many, many events A program can respond to an event if the programmer writes an

event procedure

  An Event Procedure is a block of code that executes only when particular event occurs Writing an Event Procedure  Create the event procedure stub ▪ Double click on control from Design Window – for default event for that control OR ▪ ▪ Open the Code Editor (F7 or View Menu/Code option) Select Control & Select Event from drop down windows in Code Editor  Add the event code to the event procedure stub

 Select the btnWelcome control from the Form Controls List Box

  Select the Click event from the list of many available events Buttons have 57 possible events they can respond to

 Beginning of Procedure is created for you  If you create stub by double clicking on control it will create a stub for the most commonly used event for that control

 Write the code that you want executed when the user clicks on the btnWelcome button  Type: MsgBox (“Welcome to Visual Basic”)  Must be contained within the Event Procedure Stub

  Not Case Sensitive  Visual Basic will “correct” case issues for you Keywords are in Blue    Special reserved words Comments in Green Problems with Syntax (Language) will be underlined in blue

 Rules   Use spaces to separate the words and operators  Indentation and capitalization have no effect Recommendations  Use indentation and extra spaces for alignment  Use blank lines before and after groups of related statements  Code all variable declarations at the start of the procedure  Group related declarations

 Usage  Type an apostrophe ( ' ) followed by the comment  The compiler ignores everything on the line after ‘   Used for documentation/readability and to disable chosen statements during testing Recommendations  Follow apostrophe with a star for readability ( ‘* )  Use at beginning of program to indicate author, purpose, date, etc.

 Use for groups of related statements and portions of code that are difficult to understand

'* ====================================== '* Class: CIS 115-101 '* Author: Paul Overstreet '* Purpose: Homework 1 – VB Application '* Date: 11/30/01 '* ====================================== Public Class Form1 Private Sub btnCalculate_Click( ByVal sender As System.Object, ByVal e As System.EventAr… '*Variable declarations Dim dOrderTotal As Decimal Dim dDiscountAmount As Decimal '*Get total from textbox dOrderTotal = txtOrderTotal.Text

'*Calculate the proper discount dDiscountAmount = dOrderTotal * 0.25

' dDiscountAmount = dOrderTotal * 0.25

End Sub Private Sub Button1_Click( ByVal sender As System.Object, ByVal e As System.EventArgs)… ‘*Code goes here End Sub End Class

   Create an Event Procedure for when the btnExit button is clicked Have it display “Goodbye” in a MsgBox Then “End” – this will terminate the program

  You can switch between the Design Window and the Code Window (once opened) by clicking on the tabs at the top of the Design and Code Windows  Form1.vb(Design) is the  design window  Form1.vb is the Code Window

  Click the Run Icon on the Standard Toolbar Or Press F5    This will begin the program Display the Form/Window Nothing will happen  Waiting on an Event

  Click on the “Say Welcome” button  The message box should display Click on the “Exit” button  The message box should display  The application should terminate

 Make sure to save your work  SAVE ALL (not Save Form)  Visual Basic applications are  made of several files  Often even several forms

 Lab Handout  Intro to VB Controls and Properties  See handout for details and due date  Questions?