An Introduction to Visual Basic 'NET and Program Design

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Chapter 1

• An Introduction to Visual Basic .NET and Program
  Design

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Objectives

• Describe Visual Basic .NET
• Describe the VB programming language
• Programs, programming, applications, and program
  development
• Identify each of the phases in the development
  cycle
• Define an algorithm
• Explain object-oriented programming (OOP)

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Introduction

• A program is a step-by-step series of
  instructions
• Programming is the process of writing these
  instructions
• Programmers, or software developers, design and
  write programs
• An application is a collection of one or more
  programs
• Program development is the process of writing
  applications

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Example 1 Recipe
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Example 2 Flowchart

• Flowcharting to help communicate what actually
  happens or needs to happen.

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Computer Program
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Program Execution

• Stored program instructions are loaded into
  memory before their execution
• Machine Cycle
• Fetch
• Decode
• Execute
• Stored

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Microsoft Visual Basic .NET?

• Programming environment that allows you to build
  programs for the Windows operating system or any
  system that supports Microsofts .NET
  architecture
• Based on the Visual Basic programming language
• Evolved from BASIC (Beginners All-purpose
  Symbolic Instruction Code)

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Visual Basic .NET?
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Window Applications

• Graphical User Interface (GUI)
• Components include menu, button, textfield

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Web applications

• Needs a Web browser to run
• The VB.NET program is converted to HTML
  instructions

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Console Applications

• Input/output on DOS command prompt

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Windows Services

• Program performs maintenance, information
  gathering, security and notification tasks
• No user interaction needed

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Web Services

• Program provides information to another program
  (Web application) over the Web
• No user interface

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Components

• VB.NET creates components for other programs to
  use
• Reusability components can be reused over and
  over by many programmers

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The Development Cycle
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Phase 1 Analyze Requirements

• Verify the requirements are complete
• Make the initial determination that it is
  possible to solve the problem
• List input and output data required
• Determine whether the input data is available for
  testing
• Ensure that the information provided explains how
  to convert the input data into output data so
  that a solution, or algorithm, can be developed

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• Provided by customers or users
• Lists the functions and features

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Phase 2 Design Solution

• Develop a logical model that illustrates the
  sequence of steps you will take to solve the
  problem
• Design methods include object diagram,
  flowcharts, pseudocode, and storyboards.

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Phase 2 Design Solution

• Objects are smaller pieces of a program
• Object model
• Attributes
• Methods

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Phase 2 Design Solution

• Flowchart represents the logic of an algorithm
• Control structures specifies the execution of the
  code

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Phase 2 Design Solution

• Pseudocode expresses the step-by-step
  instructions, and depicts logical groupings or
  structures

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Phase 2 Design Solution

• Storyboard shows how the application window or
  Web page will look

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Phase 3 Validate Design

• Validate, or check, the program design
• Step through the solution with test data
• Compare the program design with the original
  requirements

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Phase 4 Implement Design

• Write the code that translates the design into a
  program
• Create the user interface
• Create comments to explain the purpose of the
  code
• Test the code as it is written

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Phase 4 Implement Design
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Phase 5 Test Solution

• Test plan
• Test cases
• Integration testing
• Boundary values

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Phase 6 Document Solution

• Includes the requirements documents, program
  design documents, user interface documents, and
  documentation of the code
• Code should be archived electronically

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Object-Oriented Programming

• Object-oriented programming
• Data and the code that operates on the data are
  packaged into a single unit called an object
• Object-oriented design
• Represents the logical plan of a program as a set
  of interactions among objects and operations

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Rapid Application Development

• The use of pre-built objects to make program and
  application development much faster.

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Rapid Application Development

• Control (like a button) has properties such as
  color or width.
• A control may create events that trigger compute
  to act. When an event occurs, a message is sent
  to a method in a control, and the control is
  programmed to respond.

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What is .NET?

• It is a common environment in which programmers
  can create applications.
• It provides a rich set of classes (.NET framework
  class library)

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The Common Language Runtime

• Applications executes on an intermediate .NET
  system, the Common Language Runtime.
• The .NET applications consist of language that
  CLR understands, called the Microsoft
  Intermediate Language (MIL).
• Two different applications, Visual Basic and
  Visual C, will have same MIL