Applications Development

1. Applications Development Using VB .Net Note: The prerequisits of this course are CMP210, CMP218 or CMP219 and CMP252

2. Learning new languages

3. Computer Programming Languages • Can be classified into two basic types • Object Oriented Programming • Procedural Programming • Each computer language classified under each “type” will follow specific guidelines. • knowing the specific guidelines within a language type will help in learning the different languages within each type.

4. Computer Programming Languages (Continued) • Procedural Languages • Examples include • PASCAL • C • COBALD • Follow a top down design • Object Oriented Languages • Follow OOD (Object Orient Design) • Examples include • C++ • Java • VB .Net

5. Object Oriented Languages Overview (Review questions) • Some questions that should be answered as a review. • What is OOP (Object Oriented Programming)? • What are Data Types (Primitive and Abstract)? • What is the String Data Types and its associated methods? • How do you convert numeric data from a String to a Primitive data type? • What is the difference between a class and an object? • What are attributes? • What are methods? • What is a constructor? • What is an Accessor? • What is a Mutator/Modifier? • What is inheritance? • What are loops? • What is Exception Handling and Why is it used? • What does public and private mean? • What are control structures (if and switch statements) • What are the following operators • Assignment? • Math? • Comparison/Logical? • Boolean?

6. Classes in OOP • Are object descriptions • Contain both attributes and methods • Attributes are data types that describe the object • Can be both Primitive data types and other classes • Can be public or private • Methods are the actions that the object can do • Three types of methods • Constructor • Accessor • Mutator/Modifier • Every method contains a specific format • Every method contains an accessibility (public/private) • Every method contains a parameter lists (lists can be empty) • Every method contains a return type (can be void or nothing)

7. Learning VB .net Comparing VB .net and Java

8. Similarities of VB .net and Java • Both are object oriented • Both have public and private methods and attributes in a class • Both use exception handling • Both are event driven programming languages

9. Noticeable differences between Java and VB .net • VB .net does not use semicolons • VB .net does not use curly braces • VB .net is not case sensitive • VB .net contains both Sub Procedures and Functions • VB .net primarily contains a visual interface for the programmer • VB .net runs on multiple platforms containing the VB .net environment • Every program in this class will start off with a form.

10. Primitive Data Types in Java • int • float • double • boolean • byte • char • Long • Etc.

11. Primitive (elementary) Data Types in VB .Net • Integer • Boolean • Decimal • Date • Double • Char • String • Etc.

12. Converting Data Types in VB .net • Functions are used to convert text (String) data to numeric data • These functions include • CInt() • CDec() • CLng() • Etc. (in text on page 485) • These functions in VB .net behave much like the parsing methods in Java.

13. Operators in VB .net • Math • + • - • * • / • Mod (Modulus or Remainder) • Assignment • =

14. Operators in VB .net (continued) • Comparison • = (the same as assignment) • < • <= • > • >= • <> (Not equal) • Boolean (uses words not symbols) • And • Or • Not

15. Variable declarations in VB .net vs. Java • In java the data type is placed before the label int num1; • In VB .net • All variable declaration requires the keyword Dim (stands for Dimension) • the label is placed in front of the data type • Option Explicit and Option Strict should be also turned on at the top of every class Dim num1 AsInteger

16. Method Syntax in Java publicint Sum3 (int num1, int num2, int num3) { int answer; answer = num1 + num2 + num3; return answer; } • The return type is an integer • The number of parameters are 3 integers • The method is public

17. Methods in VB .net • VB .net have two specific types of methods for classes • Each method could still be • A Constructor of a class • An Accessor of a class (Called Property get) • A Mutator/Modifier of a class (Called Property set) • The two specific types are • Sub procedures (do not return a value) • Functions (return a value)

18. Functions in VB .net • Functions can be both public and private • Functions return a value • The return type of the Function is always at the end of the method heading (different than Java) • Only one value may be returned from a Function • Functions contain a parameter list

19. Method (functions) Syntax in VB .net PublicFunction Sum3(num1 AsInteger, num2 AsInteger, num3 AsInteger) AsInteger Dim answer AsInteger answer = num1 + num2 + num3 return answer EndFunction • This Function is public • This Function contains 3 parameters of type Integer • This Function has a return type of an Integer

20. VB .Net Specifics for developing windows applications

21. Forms in VB .Net • Every form in VB .net is a class • Forms have default attributes (properties) and methods (sub procedures and functions) • Properties can be set with the properties Window in the .net development environment

22. Forms in VB .net (Continued) • Properties that can be set are • Text (Title in the title bar) • Background color • Name of the form (Like java should match the name of the file (class name) • Size • Icon (in the Title bar) • Etc. • Forms can also have attributes (properties) and methods (Functions and Sub Procedures) added to them

23. Controls in VB .net • Items added to the form such as text boxes are called controls • Each control added to a form becomes an attribute of that form (or part of the form) • Each Control is an Object and have • Attributes (properties) • Methods (Functions and Sub-Procedures)

24. Controls in VB .net (Continued) • All properties can be set by using the properties window for each control. • Controls in VB .net include • Text Boxes • Buttons • Data Grids • Etc.

25. Text Boxes • Used for entering text for a windows application • ALL Data entered in the text box is a String (like with JOptionPane) • All numeric data must be converted with the methods described earlier • The Text attribute will hold the Data entered into the text box

26. Events and Windows Applications • Windows is an event driven operating system (Flow of control is driven by events that occur) • Events are messages that are passed to applications and objects when something in the program occurs • Events can be a mouse click, positions of the Mouse etc.

27. Buttons and Event handling • By double clicking on the Button control on the form, sub program headings for handling the click event are inserted. • All code that is entered into the event handler will only execute in the program when the button is clicked. • another event that is handled in programs written in class is the Form load event.

28. Control Structures in VB .net Similarities and differences between Java and VB .Net

29. If statements in Java if (num1 == 4) { System.out.println(“num1 is 4”); }else { System.out.println(“num1 isn’t 4”); }

30. If Statements in VB .net If num1 = 4 Then MessageBox.Show(“num1 is 4”) Else MessageBox.Show(“num1 isn’t 4”) EndIf

31. VB .net If statements (continued) • Again no semicolons • No curly braces • End If ends the if statement • Single equal sign is used for comparisons and assignments