Visual Basic .Net

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Visual Basic .Net

• Seminar June 7, 2004

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Topics Today include

• The .Net Framework
• Studio .Net Environment
• VB .Net
• Introduction to VB .Net
• Loops and Control Structures

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The .Net Framework

• What is the .Net Framework
• Common Language Runtime
• .Net Managed Assemblies
• Compilation of .Net Code
• .Net Framework Class Library
• .Net Languages
• The future of .Net

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What is the .Net Framework

• Primarily a development platform (mostly effects
  application development)
• Consists of two main parts
• Common Language Runtime
• .Net Framework Class Library

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CLR (Common Language Runtime)

• Provides a runtime environment for the
  execution of code written in ANY .Net Language
• Manages
• The overall execution of .Net code
• Inheritance, Memory, Debugging, and application
  development across Multiple languages

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CLR (Continued)

• Languages that utilizes the .Net framework must
  follow the CLS
• Common Language Specification
• Outlines the rules and standards required or
  needed by the CLR to execute .Net code.
• The CLR will execute Managed Assemblies
• Intermediate Languages managed by the CLR are
  called Managed Code
• The CLR will manage for the IL
• Garbage collection
• Object instantiation
• Memory allocation
• Components written in Managed Code by the CLR are
  called .Net Managed assemblies

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.Net Managed Assemblies

• Basic Unit of deployment of .Net Applications
• Similar to the Microsoft COM Objects
• Each Managed Assembly contains a Manifest
• Hold definitions of other components required for
  execution of the application
• Prevents the problems associated with conflicting
  DLLs
• Revision numbers and components are listed in the
  manifest
• Two versions of the same DLL can then co-exist

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Compilation of .Net code

• All .Net languages are first compiled into an
  intermediate language called MSIL or IL
  (Microsoft Intermediate Language)
• The MSIL is then Just In Time (JIT) compiled at
  first execution of the code and managed by the
  CLR
• All MSIL or IL code can be compiled directly to
  native code with the following
• Compiling native code will provide faster startup
  execution of the code
• Performance during execution of the code will
  then be sacrificed
• During JIT Optimization is placed on the Managed
  Code in order to improve performance at the time
  of execution

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.Net Framework Class Library

• Provide a library of base classes that developers
  can use in their own applications written in ANY
  .Net language
• Because of the use of these base classes,
  Inheritance can then be extensively used in
  languages that use the .Net Framework

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.Net Languages

• .Net applications can be written by any or a
  combination of many .Net languages
• Languages include
• VB .Net
• C
• J
• Managed C (default in studio is set for managed
  C)
• Applications can be developed without the use of
  Studio .Net
• Applications can be developed still using a
  simple text editor
• ASP .Net Applications as well as other apps can
  be still developed using notepad

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The future of the .Net Framework

• Standards were release in 2000 from Microsoft to
  the community
• GNU .Net is a project in the Linux community that
  is presently developing a CLR to run in the Linux
  environment
• Languages planned to include the CLS are
• APL
• COBOL
• Eifel
• Fortran
• Haskel
• Mercury
• Mondrian
• Oberon
• Pascal
• Perl
• Python
• RPG
• Scheme

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Studio .Net EnvironmentThe IDE

• Studio .Net
• The Start Page
• Problems with Studio .Net in the lab environment

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Studio .Net

• All present .Net languages are included under one
  development environment
• When using any one of the languages, the studio
  must be used (there is no longer an environment
  for each language)
• You have to start a new solution/project
• Projects are containers that contain the files
  associated with a particular project
• A solution is a container that contains one or
  more projects or project containers
• When the IDE is started you have the Projects
  tab, online resources, and My Profile

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The Start Page
Profile and environment settings
Tab for Additional Help
Tab for this view
Previous Projects
Open a project in a diff. location
Start a new project
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Problems with Studio .Net environment in the lab

• .Net security must allow access to the J drive
  or the local intra net in order to work properly
• Problems arise when debugging apps on an ASP .Net
  server that is not part of the current domain
  (CLC) Basic apps will still work fine
• These problems are not present if IIS and remote
  debugging tools are installed on the client
  machine
• This solution is fine for students but is not
  practical for a lab
• Due to security holes of IIS you can have
  hundreds of security risks on a given network.
• In the Real world situation, all apps will be
  placed on a server anyway

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Visual Basic .Net

• General Features
• Additional Features of VB .Net
• What has changed in VB .Net

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General features

• It is an object oriented language
• Students do better with this subject when they
  have a firm understanding of objects
• In the past VB had objects but focus was not
  placed on them
• VB .Net use objects and inheritance with
  everything
• Uses exception handling extensively
• New techniques are shown to the student for
  providing feedback from their programs in order
  to help trouble shoot errors
• Like with most OOP languages, exceptions that are
  not handled will cause programs to abnormally end
  or exit
• Uses generics with creating classes and Sub
  programs
• Can use the top data type on inheritance of type
  Object
• Used for late binding of data types and is quite
  useful when implementing stacks or queues of any
  data type (.Net 2.0)
• Provides a quick way to develop heavy duty
  applications in a windowing environment
• It is a useful tool for developing event driven
  programs

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Additional Feature of VB .Net

• Can create both windows applications and web
  applications at the click of a mouse button
• The interface between the Databases and
  applications
• Are the same between web apps and windows apps
• All data are transferred between the apps in XML
  format regardless if it is a web application or a
  windows application
• A copy of the data from the database is loaded
  into a data set.
• Persistent connections between the application
  and the database no longer exists
• Every form is a class and new forms now have to
  be instantiated
• VB .Net is still not case sensitive

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What is Not in VB .Net

• Data Controls
• Because of the different way that the apps
  connect to the database, there is no longer the
  support of data controls in VB .Net
• Persistent connections with the database is no
  longer present
• Object instantiation is now done differently
• Garbage collection for references that lose there
  objects are done periodically not when the
  reference lose its scope
• Periodic changes throughout the language making
  it vastly different from VB 6.0 in order to make
  it compliant to the .Net Framework and the CLS

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The Introduction to VB .Net

• Data Types in VB .Net
• Functions and Sub Procedures
• Practice Examples

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Data Types in VB .Net

• Data Types and possible values
• Integer -gt -2,147,483,648 (4 bytes)
• Double -gt floating point numbers with 14 digits
  of accuracy (8 Bytes)
• Decimal -gt decimal values ( 16 bytes replaced
  currency in 6.0)
• Date -gt the date (8 Bytes)
• Byte -gt 0 to 255 (1 Byte)
• Char -gt Unicode character (2 Bytes)
• Boolean -gtTrue or false value (2 Bytes)
• Single -gt floating point number with 6 digits of
  accuracy (4 bytes)
• Short -gt 2 byte integer
• Long -gt 8 byte integer
• String -gt an arrangement of alpha-numeric
  characters varies in length
• Object -gt any data type 4 bytes

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Functions and Sub procedures / Programs in VB
.Net (Methods)

• Functions and sub procedures must either have a
  sub or function keyword in the function or sub
  procedure heading
• They can be either public or private (following
  the same conventions in OOP languages such as C
  or Java)
• All parameters are passed by value by default in
  VB .Net
• Parameters of any data type may be passed by
  reference
• All Objects and arrays are passed by reference
  not value
• All events are handled by a sub procedure in VB
  .Net
• Functions return a value and Sub Procedures do
  Not

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Practice example 1

• You can use the text book given to you to get the
  basics needed in programming VB starting on page
  477
• Getting familiar with VB .Net
• Write a program that will take text from one text
  box and place that text in another text box with
  a click of a button
• Take a look at the attributes of each control
• A control can be a button text box etc.
• Each control should contain names that follow VB
  specifications i.e. txtBox1 txtBox2 btnMove
• Each name as always should be meaningfull

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Practice Example 2

• Using Functions in VB .Net
• Use the text boxes from the previous example
• Add a text box
• Provide a function that adds the values of text
  box 1 and text box 2
• Place the answer in text box3
• Use variables of type double and use the CDbl()
  function to convert the string value of the text
  box to a double page 485 in your text

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Loops and control structures

• The If Statement
• The Select Case Statement
• The Do While and Loop While loops
• The For Loop

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The IF Statement

• Every If statement must contain a then and an end
  if
• Example
• If Num1 lt 2 Then MessageBox.show(The value
  is less than 2) End If
• If Num1 ltgt 4 then MessageBox.Show(The value
  is not 4) End If
• The relational operators that can be used in VB
  are
• gt
• lt
• gt
• lt
• ltgt (Not equal to)

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The Select Case statement

• The select case statement is a lot like the
  switch statement in Java
• It can use ANY data type in VB
• Example
• Select Case Num1
• Case 1 DoSomeThing()
• Case 2 Do SomethingElse()
• End Select
• Yes you can use strings as well

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Do While Loops

• Do while loops evaluate the expression first then
  executes the Loop Body
• Act much in the same as All While loops in
  languages like C and Java
• Example
• Do While Num1 lt 10
• Num1 1
• Loop

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Loop While Loops

• The Body of the Loop is executed first then the
  expression is evaluated
• The loop will execute at least once
• This is a lot like the do while loop in Java and
  students get confused with this subtle change
• Example
• Do
• Num1 1
• Loop While Num1 lt 10

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End Of Day 1
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VB .Net Seminar Day 2

• June 8, 2004

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Microsoft SQL Server

• MS SQL Basics
• The Enterprise Manager
• Creating Databases
• Connecting to Databases
• The use of the Data Set
• Exception Handling

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Microsoft SQL Basics

• Differences between MS SQL and Access
• Advantages of MS SQL
• Quirky things with SQL
• Connecting to the database with the manager

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Differences between MS SQL and Access

• SQL More Powerful than MS Access
• Larger data types are available
• Connection over a network provide access to
  multiple clients
• Blob data type available
• A client is required to connect to the SQL
  Database

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Advantages of MS SQL

• Can handle multiple users at one time
• Ideal for web sites and web applications
• Contain the BLOB (Binary Large Object) which
  enables a user to store images in a database
• Larger numeric values can be stored in each field

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Quirky problems with SQL

• No Auto Number Data Type in MS SQL
• Auto number is an integer data type
• Identity is set to yes
• And the seed is set to one
• This gives you the option to set the starting
  number and the increment you want the auto number
  to have

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Enterprise Manager

• Connecting to the database
• Getting through the confusion of locating
  databases
• Defining the different containers in the Manager

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Connecting to the DBMS

• Start the Enterprise Manager
• Right Click SQL Server group

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Connecting to the DBMS

• Click on SQL Server Registration
• Click next
• In the text box labeled Available Servers type
  Sigma.vbnet.matcmp.ncc.edu
• Click Add then next

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Connecting to the DBMS

• Click on SQL Server login
• Username is the first six letters of your last
  name and your first initial
• Password is vbnet
• Click next and click next again
• Click Finish
• Click close on the next dialog box

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Getting through the concussion

• MS SQL Enterprise Manager will display ALL of the
  databases located on the server
• Access to each database is controlled by the DBMS
• ALL tables are displayed in each database
• This includes tables that are used by the DBMS

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The Containers in SQL

• Each container has a specific role
• Student Databases are in the databases container

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Database Container

• Every students database is displayed
• Only the database that the student has
  permissions for can be opened
• Click on the database container with your username

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Student Database container
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Creating the Database

• Creating tables
• Properties of the data types
• Entering and Displaying Data in database Tables

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Creating Tables

• Right click on the table container
• Click new table
• This is a lot like the Access interface with
  different data types.
• At this points explore the interface and notice
  the differences

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Properties of Data Fields

• Each Data Field has a length property
• This sometimes causes a problem with students who
  make this field too small
• Each data Field can also allow null values
• After defining each column and setting all the
  properties set the primary key by right clicking
  on the field that is to be the key

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Entering and Displaying Data

• Right Click the table
• Click Open Table
• Click Return All Rows
• From here you can view and enter new data into
  the table

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Practice Example 1

• Creating a Table in VB .Net
• Create a table of customers in a hardware store
• Columns will include
• Customer ID
• First Name
• Last Name
• Address
• Zip Code
• Fill the table with data
• Display that data

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Connecting to the database with VB .Net
Applications

• The Data Provider
• The Data Set
• The use of the wizard

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The Data Adapter

• Needed to connect to every DBMS
• Must Use the Adapter that represents the DBMS you
  are going to use
• We are going to use the SQLDataAdapter Object
• Holds the information on how to

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The Data Provider

• Manipulates data through the use of SQL
  statements or commands
• Hold connection information to the Database
• Contain two Major components
• Data Adapter Object updates data in the dataset
• Connection Object maintains the connection

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The Data Set

• Holds data returned from a procedure or Query
  performed by the data adapter
• Provides a local Copy of the data from the
  table on the local machine
• Prevents persistent connections with the database
  and reduces network traffic

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The use of the wizard

• Give Demo on using the wizard

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The Data Set

• Generating the data set object
• The use of the onload event handler
• Binding controls
• Creating navigation for a database

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Generating the Data Set Object

• Once the Data Adapter and the connection object
  is created click on Data in the menu
• Click generate dataset
• Give a name to the dataset
• Click OK

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The use of the onLoad event Handler

• Double click the form
• Place the fill method in the Load event handler
• This will fill the dataset object with the data
  from the table when the form loads
• Example
• SQLDataAdapter1.Fill(MyDataSet1)

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Binding Controls

• Once you create a data set you can then bind the
  controls of the form to fields or columns of the
  database table
• This is done with in the Bindings property in the
  text box properties sheet
• Under the bindings property click text and then
  the field you wish to bind to the text box

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Creating navigation for a database

• Managed by the BindingManagerBase Object
• This object contains the Position Property the
  holds the current position of the record in the
  dataset
• This is done by adding one to the position
  attribute of the object
• Methods of this object includes
• Addnew()
• EndCurrentEdit()
• CancelCurrentEdit() -gt provides a role back
  feature
• RemoveAt() -gt deletes current row at given
  position

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Exception Handling Implementation

• Use try catch block much the same in Java
• Can help trouble shoot connections to databases
• Very important to use when filling the dataset
• Example
• Try
• SqlDataAdapter1.Fill(DataSet11)
• Catch ex As Exception
• MessageBox.Show("Error will dataset
  fill")
• End Try

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Practice Example 2

• Connecting a form to your Hardware customers
• Create a form with text fields for each column
• Create the data Adapter and Data Connection with
  the use of the wizard
• Create the data set object
• Create the onload event handler to fill the data
  set
• Bind your controls
• Be sure to use exception handling for filling the
  data set
• Create a Next button to navigate to the next
  record in the database

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End Of Day 2
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VB .Net Seminar Day 3

• June 9, 2004

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Topics

• Adding and Editing Records
• Updates and deletes with Bound controls
• Classes and Modules in VB .Net
• Menus
• From design
• MDI (Multi Document Interfaces)
• Bound and unbound controls in VB .net
• Why Unbound controls are used

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Adding and Editing Records

• When Adding records
• The Position of the dataset should be set to the
  end
• The text boxes should be cleared
• The AddNew() Method accomplishes all this in one
  method call
• The AddNew() Method is part of the
  BindingManagerBase Object
• When changes are being made, a cancel button
  should be provided to Roll Back changes made to
  the data set

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Edit

• When Navigating the database the Text boxes
  should be disabled to prevent changes
• There should be an edit button that
• Disables the navigation button
• Enables the text boxes for editing
• Provide a cancel button that Roles Back the
  changes that are made by calling the
  CancelCurrentEdit() method of the
  BindingManagerBase Object

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Update and Deleting Records

• This is done by
• Ending the current edit by calling
  EndCurrentEdit() in the BindingManagerBase class
• Updating the DB with Update() in the data adapter
• Cause the dataset to reflect the changes by
  calling the AcceptChanges() method in the data
  set
• Deleting the records
• First Ask the user if they are sure they want to
  delete
• Use the RemoveAt() method of the
  BindingManagerBase object
• Update the database with the Update() method
• Have the dataset reflect the change by calling
  the AcceptChanges() method of the dataset object

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Practice Example 1

• With the Example finished yesterday
• Add an Add Button
• Add an Edit Button
• Provide a Save and a delete feature
• Use exception handling for everything

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Classes and Modules in VB .Net

• Creating classes in VB .Net
• The constructor and Sub procedures in VB .Net
• The use of Modules

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Creating Classes in VB .Net

• Classes can be added to a project by
• Right clicking the project container
• Click add
• Click add class
• As in Most OOP Languages VB classes have
• Public and private attributes
• Public and private Methods (called functions or
  sub procedures)
• Constructors and Destructors (destructors are not
  really needed in VB because of garbage collection)

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Modules

• Modules can also be added to a project to provide
  a place for Global Methods and Identifiers
• These Identifiers and methods can be either
  public or private
• Public Identifiers and methods can be accessed
  from all of the forms and classes in the VB
  project

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Practice Example

• For this Example
• Create an Auto Class
• An Auto will have
• Three Attributes
• Three Methods
• Two constructors
• Try instantiating the method in the form

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Menus

• When adding menus to a form you can type in the
  choice right into the menu object
• Click event handlers can then be added for each
  menu choice in the same manner as the button

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Form Design

• Colors are important
• They should be contrast in color
• Ease to read
• Easy on the eyes for long periods of viewing
• Should provide easy navigation
• Should provide a way to enter the data easily
  with just using the keyboard

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Multi Document Interfaces (MDI)

• When creating a form in VB .Net you are creating
  a class
• Every class in vb must be instantiated before it
  is used
• This is accomplished by using the new keyword
• When the instance of the form is created, the
  form can then be visible by calling the forms
  show method
• Closing a form does not exit the program. To
  exit the program the End method should be called

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Practice Example 3

• Create a Form that will be a switch board
• Add a form to yesterdays example
• Place a button that will open the customer form
• Place a button that will exit the program

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Bound and Unbound Controls

• So far we have seen the benefits of bound
  controls
• These are ok if you intend to use the same SQL
  query for the whole application
• Once controls are bound to a data set, changes to
  the query in the data adapter can not be
  accomplished
• Unbounded controls give you the power to create
  new data adapters with new queries.
• Values can then be placed into the query to find
  specific records in a database

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End Day 3
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VB .Net Seminar Day 4

• June 10, 2004

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Topics

• ASP .Net basic applications
• ASP .Net Database applications
• Web Forms
• Crystal Reports
• Creating Help Files
• Demo with Serial port programming and VB .Net
• Handout Certificates

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ASP .Net basic Applications
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End Day 4