CSCI 3328 Object Oriented Programming in C# Chapter 1: Introduction to C#

1. CSCI 3328 Object Oriented Programming in C# Chapter 1: Introduction to C# Xiang Lian The University of Texas – Pan American Edinburg, TX 78539 lianx@utpa.edu

2. Objectives • In this chapter, you will • Know requirements of this course • Recall basic components in a computer system • Learn the evolution of programming language • Refresh your memory about the object-oriented programming • Become aware of the .Net Framework for Visual C#

3. Background Required • C++ Programming • If you made an A in 1370/1170 you will do fine with some effort • If you have already taken 2380, you will find this course not very difficult • You need to be able to look up how to get things done (for example, look up syntax)

4. Programming, Programming, Programming • This class is unlike other courses in that you will spend a lot of time doing actual programming • You should never copy a program from someone else • Even if your program does not perform as good as someone else’s, you should submit what you have • You should not hesitate to ask questions in class

5. Assignments • Unless I announce it, programs are due in one week after assignment is given in class, or posted • Occasionally, I will give two weeks for difficult programs • You should work on a program the same day it is assigned • That way you can ask questions during the following class period

6. Use of the Textbook • I will not be covering chapter by chapter • I will cover important points needed to complete the assignments • You need to search the index in the back to find the topic needed for each assignment • You can also obtain help from MSDN at the Microsoft site

7. Versions of C# • You can program using 2008 or 2010 • Our book only covers 2008 • Usually it takes a year or so for new books to come out • If you use 2010, you have to find help from other sources or the Web

8. The Time for Class • I expect to hold the class for little over an hour each time • Remaining time should be spend with your assigned groups to discuss the project in class • Please do not exchange programs with each other, just ideas

10. CSCI 1380: Elements of a Computer System • Hardware • CPU • Main memory • Secondary storage • Input / Output devices • Software • System programs • Application programs (e.g. Visual Studio)

11. Programming Languages • Machine language • Assembly language • High-level language • E.g., C#

12. Object Technology • We humans are very good in recognizing and working with objects, such as a pen, a dog, or a human being • We learned to categorize them in such a way that make sense to us. • We may categorize them as animate object, inanimate objects, pets, friends, etc.

13. Object Technology (cont'd) • We some times classify objects based on their attributes, for example, green apples or red apples, fat or slim people, etc. • If you think about it each object has many attributes. • If I ask you list the attributes of an orange, you probably could list many things such as color, shape, weight, smell, etc.

14. Object Technology (cont'd) • In addition to attributes, all objects exhibit behaviors. • A dog eats, barks, wags its tail, plays, and begs. • A dog exhibits many more other behaviors than this short list. • Another thing we need to remember about objects is that objects interact between each other

15. Object Technology in Visual C# • Visual C# • Object-oriented • E.g. forms, labels, buttons, radios, checkboxes, etc. • Properties of objects • E.g. background color of forms • Event-driven • Behaviors  events of objects • E.g. clicks

16. .Net Framework • A software platform • Language-neutral • Designed for cross-language compatibility • Applications written in C# may reference a DLL file written in any other language • 2 components: • Common Language Runtime (CLR) • Class Libraries

17. The .Net Framework • Underneath the applications you develop using C# is the .Net Framework containing a library of classes needed for windows forms and web forms. • The .Net framework interacts with the Common Language Runtime (CLR), which in turn interacts with the operating system and the hardware • This way programs you write using C# can run on different operating systems and hardware platforms as long as it has the correct version of the .Net installed on it

18. Common Language Runtime • Execution Engine of .Net • Manages the execution of programs and provides core services: • Code compilation • Memory allocation • Thread management • Garbage collection

19. Class Libraries • Designed to integrate with the common language runtime • This library gives the program access to runtime environment • The class library consists of lots of prewritten code that all the applications created in VC# .Net and Visual Studio .Net will use • The code in Visual C # for all the elements like forms, and controls actually comes from the class library

20. Namespaces • Within the .Net Framework, related classes are grouped into Namespaces • You need to insert a “using AppropriateNamespace” in your program • After that you can refer to methods and attributes of classes contained therein

21. To Get .Net Namespace Documentation • Visit: http://msdn.microsoft.com/en-us/library/ms229335.aspx

22. How Do You Write and Run a Program? • Use the Visual Studio to create a project • File New  Project… • The project file will have the extension *.csproj. The project stores all related files, including the source file you write. Every project has a solution file with the extension *.sln. You would be opening this file when you want to return to your program you were writing. This will open all associated files. The associated files may be contained in a subdirectory. • After writing the source code, go to Build and build your solution, which creates the intermediate code • Go to Debug and start without debugging • The program run will finish and give you a prompt to press any key to continue. Starting with debugging, it will complete the run and return to you to the IDE. If your IDE does offer “without debugging”, add a Console.ReadKey() statement.

23. Options for a New Project • Console application • Windows forms application • …

24. Hello Program using System; //using System.Collections.Generic; //using System.Linq; //using System.Text; namespace sayHello { class sayHello { static void Main(string[] args) { Console.WriteLine("Hello!"); Console.WriteLine("Welcome to Dr. Lian's C# Class!"); Console.ReadLine(); } } }

25. Using the Form Designer • You can size the form by holding the handles in the corners or the middle • Controls and other items are added to the form using the toolbox • The control or item has properties that can be set • To write the code for an event, you can click on the view code button above the solution explorer or by simply clicking on a button or anything else on the form • Files with code you write will have extension .cs • Files ending with designer.cs are code files generated by Visual Studio

26. Naming Controls and Boxes • Use a convention you will remember • You can start all button names with btn • An accept button will be named btnAccept • An exit button will be named btnExit • All text boxes will start with txt • Sales amount will be named txtSalesAmount • All labels with start with lbl • lblEnterName • It is up to you to choose naming conventions you will recognize

27. Your First Assignment • Assignment #1 • The purpose of this assignment is to practice reading and writing to console using C#. It is a simple assignment. Use the following program run to design and write your program. Please submit Program listing and a screen capture of the program run. Follow the textbook examples to add comments as documentation.

28. Assignment Submission • Make sure to include your name, assignment number, date due and date completed on each assignment you submit • Assignment should be submitted in a manila folder with your name and assignment number appearing on the tab • Submit your assignments to the Blackboard

29. Exercises • Give a brief explanation of the .NET framework • What is the Common Language Runtime? • How do you place “Total Square Feet: 1238” in a text box? Assume that 1238 in an integer stored in a variable called sqFt.