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Visual Basic .Net

Visual Basic .Net

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Visual Basic .Net

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  1. Visual Basic .Net Seminar June 7, 2004

  2. Topics Today include • The .Net Framework • Studio .Net Environment • VB .Net • Introduction to VB .Net • Loops and Control Structures

  3. 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

  4. 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

  5. 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

  6. 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

  7. .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 DLL’s • Revision numbers and components are listed in the manifest • Two versions of the same DLL can then co-exist

  8. 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

  9. .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

  10. .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

  11. 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

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

  13. 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

  14. The Start Page Profileand environmentsettings Tab for Additional Help Tab for this view Previous Projects Open a project in a diff. location Start a new project

  15. 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

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

  17. 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

  18. 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

  19. 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

  20. The Introduction to VB .Net • Data Types in VB .Net • Functions and Sub Procedures • Practice Examples

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

  22. 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

  23. 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

  24. 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

  25. Loops and control structures • The If Statement • The Select Case Statement • The Do While and Loop While loops • The For Loop

  26. The IF Statement • Every If statement must contain a then and an end if • Example: • If Num1 < 2 Then MessageBox.show(“The value is less than 2”) End If • If Num1 <> 4 then MessageBox.Show(“The value is not 4”) End If • The relational operators that can be used in VB are • > • < • = • >= • <= • <> (Not equal to)

  27. 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

  28. 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 < 10 Num1 += 1 Loop

  29. 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 < 10

  30. End Of Day 1

  31. VB .Net Seminar Day 2 June 8, 2004

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

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

  34. 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

  35. 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

  36. 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

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

  38. Connecting to the DBMS • Start the Enterprise Manager • Right Click SQL Server group

  39. 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

  40. 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

  41. 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

  42. The Containers in SQL • Each container has a specific role • Student Databases are in the databases container

  43. 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

  44. Student Database container

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

  46. 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

  47. 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

  48. 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

  49. 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

  50. Connecting to the database with VB .Net Applications • The Data Provider • The Data Set • The use of the wizard