Visual Programming
Fall 2012 – FUUAST
Topic: Development environment
What will we do today
• We will create windows applications
• Introduction of .NET IDE
• Namespace, Class, Object ,Function/Method,
Access modifiers ,Properties, Events.
• Create first windows Application “Hello Wold”
Development environment
• create windows applications
Development environment
• create windows applications
Development environment
• Design environment:
Solution explorer
Menus
Form
Code editor
Toolbar
messages
Properties/events
window
Development environment
The Form – Most important - place controls – the UI.
Display by clicking Form1.cs [Design] tab
Form
Textbox
Button
Label
Listbox
Development environment
• Namespace
-
The namespace keyword is used to declare a scope. This namespace scope
lets you organize code and gives you a way to create globally unique types.
namespace BS5
{
public class Student
{
public void Get_Name()
{ }
}
public class Teacher
{
public void Get_Name()
{ }
}
}
-
Whether or not you explicitly declare a namespace in a C# source file, the
compiler adds a default namespace.
Development environment
• Class
-
The class is the fundamental building block of code when creating objectoriented software.
A class describes in abstract all of the characteristics and behavior of a type
of object.
public class Student
{
public void Get_Name()
{ }
}
• Object
-
Objects are instances of a class.
the class is just a definition. When the object is physically created, space for
that object is allocated in RAM. It is possible to have multiple objects
created from one class.
Student Std = new Student();
Development environment
• Function/Method
-
Classes contain methods that solve the problems for the program. So a
methods is a kind of building blocks that solve a small problem.
public class Student
{
public void Get_Name()
{ }
public void Calculate_Age_Number()
{ }
}
Development environment
• Access Modifiers
Access modifiers are an integral part of object-oriented programming. They support the concept of
encapsulation, which promotes the idea of hiding functionality. Access modifiers allow you to define
who does or doesn't have access to certain features.
Modifier
Description
public
There are no restrictions on accessing public members.
private
Access is limited to within the class definition. This is the default
access modifier type if none is formally specified
protected
Access is limited to within the class definition and any class that
inherits from the class
internal
Access is limited exclusively to classes defined within the
current project assembly
protected internal
Access is limited to the current assembly and types derived
from the containing class. All members in current project and all
members in derived class can access the variables.
Development environment
• Events
-
Event is a method that contains the code that gets executed in response to
a specific event that occurs in an application.
Event
Development environment
• Properties
-
A property is a member that provides a flexible mechanism to read, write, or compute the
value of a private field. Properties can be used as if they are public data members.
class TimePeriod
{
private double seconds;
public double Hours
{
get { return seconds / 3600; }
set { seconds = value * 3600; }
}
}
class Program
{
static void Main()
{
TimePeriod t = new TimePeriod();
// Assigning the Hours property causes the 'set' accessor to be called.
t.Hours = 24;
// Evaluating the Hours property causes the 'get' accessor to be called.
System.Console.WriteLine("Time in hours: " + t.Hours);
}
}
// Output: Time in hours: 24
Development environment
• Properties
Size (height and width)
Description of property
windows Application “Hello World”
Your First C# Program
• Run C#, start a new Project, > Windows Application and
call it ‘Hello world’
• Save the project. Select File>Save All.
• Display the form (click form1.cs[Design] tab).
• Add button (drag and drop) from Toolbox to form
windows Application “Hello World”
Change the button’s text display (a property).
Display the properties window,
Scroll to the Text property, type in ‘Hello world’
windows Application “Hello World”
Place TextBox and label to form
Change label’s caption property to ‘My First C# Program’.
Form looks like:
windows Application “Hello World”
Run program – not much happens. Close it.
Double-click button to add code for button click
Add code:
textBox1.Text="Hello world";
Note:
Use dot notation to access property C# is case sensitive.