Learning Dot Net with me

Object Oriented Programming Basics(OOP)

2010-02-26T14:21:00.005+01:00

Object Oriented Programming (OOP)is a recent approach to creating powerful computer applications which tends to solve the problem of procedural programming that have been in existence for long and making all functionality of a program to be in a module. The emergence of OOP has made modular method of programming popular as it gives much more flexibility opportunity for programmers.

It is programming methodology that utilizes objects to carry out functionality. This special functionality see objects or mimic them as real life entities. OOP organized object instead of actions that are also arranged around data rather than logics. As the name implies OOP is achieved using objects.

The real life illustration of OOP advantage can be given as follows: Assuming you have a car, the car is seen as a single unit with the old way of programming(procedural). If you want to improve or upgrade this car, then you will need to replace or change the whole unit by sending it back to the manufacturer or find an expert for the upgrade. But with the OOP you can simply buy the unit or part of the car that need upgrade from the manufacturer and follow their instruction to replace it yourself without need to take the whole car for the upgrade.

Advantages of OOP 1. With OOP the programs are organized around objects performing the actions;
2. Program are no longer dependent on linear logic;
3. It is easy and can be updated safely;
4. Programs relate to real life actions;
5. It makes code reuse as an acceptable action in programming; and
6. It provides agreement on the structure and usage of more abstract entities.
To read more check my blog on Dot Net @ Learning Dot Net with Me

Olufemi

Steps in creating a .NET Application

2010-02-26T01:27:00.002+01:00

The .Net framework is a strong platform for designing robust and very powerful applications. stated as follows are steps that are involved in designing application using .Net framework:

1. Application code is written using a .Net compatible language such as VB, C# or C++;

2. The code written is then complied into Microsoft Intermediate Language (MSIL);

3. When the code is executed, it must first be compiled into native code using Just-In-Time (JIT) compiler; and

4. The native code is executed in the context of the managed Common Language Runtime (CLR) along with other running application or processes.

Olufemi

Using the .NET Framework for Desinging Apllications

2010-02-23T09:08:00.001+01:00

Writing an application using the .Net means writing code (using any of the languages that support the framework) using the .Net code library.

Visual studio which is the package where one can have full access to all the .net framework capabilities; is a powerful Integrated Development Environment(IDE) that support visual C#, Visual Basic(VB), and visual C++. Visual studio expression edition in C#,VB, and C++ are free and you can download it free of charge from Microsoft Visual Studio 2008 Express Editions Download.

The advantage of these environments is the ease with which .Net features can be integrated into your code. For instance, For C# code to execute, it must be converted into a language that the target operating system understands, known as native code. This conversion is called compiling code.

Read more on my online Community IT Certification Companion

Olufemi

What is the .Net Technology?

2010-02-23T08:37:00.002+01:00

The technology contains many concepts that are tricky to come to grips with initially. The .Net framework is a new and revolutionary platform created by Microsoft for developing applications. Although the Microsoft release of .Net framework runs on the windows operating system, it is fast becoming possible to find alternative versions that will work on other systems.

Also, one can use the Microsoft .Net compact framework on Personal Digital Assistant (PDA) class devices and even some smartphone. The .Net framework allows the creation of windows applications, web applications, web services and pretty much anything else one can think of.

What is in the .Net Framework?

The .Net framework consist primarily of a gigantic library of code that one can use in client language using Object Oriented Programming (OOP) techniques. The library is categorized in to different modules you can use portions of it depending on the results you intend to achieve.

Part of the .Net framework library defines some basic types. A type is a representation of data and specifying some of the most fundamental of these(such as a 32-bit signed integer) facilitates interoperability between language using the .Net framework. This is called Common Type System (CTS).

The .Net framework also includes the .Net Common Language Runtime(CLS) which is responsible for maintaining the execution of all applications developed using the .Net library.

This is my learning note on dot net technology using VB and C#. You will learn a lot if you can keep a date with me on my online Community IT Certification companion .

Olufemi

C# Flow Control

2008-08-05T15:47:00.005+02:00

There are two methods of controlling program flow discussed in this section of our learning.
These are :

Branching : This is where code are executed conditionally depending on the outcome of an evaluation such as "only execute this code if myVal is less than 10".

Looping :This is repeatedly executing the same statement( for a certain number of times or until a test condition has been reached)

Boolean comparisons require the sue of Boolean comparison operators( also known as relational operators). In the examples below var1 is a bool type variable, while the type of var2 and var3 may vary.

1. == (var1=var2 ==var3;) var1 is true if var2 is equal to var3 or false otherwise.
2. != (var1=var2 != var3;) var1 is true if var2 is not equal to var3 or false otherwise.
3. < ( var1= var2 < var3;) var1 is true if var2 is less than var3 or false otherwise.
4. > ( var1= var2 > var3;) var1 is true if var2 is greater than var3 or false otherwise.
5. <= (var1 = var2 <= var3:) var1 is true if var2 is less or equal to var3 or false otherwise. 6. >= (var1 = var2>=var3;) var1 is true if var2 is greater or equal to var3 or false otherwise.

You might use operators such as these on numeric values in code such as :

bool isLessThan10;

isLessThan10=myVal < 10; This code result will be true if myVal store a value less than 10 or false otherwise. You can also use these compariosn operators on their types, such as strings: bool isKarli; isKarli =myString=="Karli"; In this example isKarli will only be true if myString stores the string "Karli"

There are some other Boolean operators that are intended specifically for working with Boolean values, shown below:
1. ! (var1 =! var2;) var1 is true if var2 is false or false if var2 is true (Logical NOT);
2. & (va1= var2 & var3;) var1 is true if var2 and var3 are both true or false otherwise (Logical AND);
3. | (var1= var2 | var3;) var1 is true if either var2 or var3 or both are true or false otherwise (Logical OR); and
4. ^ (var1 = var2 ^ var3;) var1 is true if either var2 or var3 but not both, are true or false otherwise (Logical XOR or exclusive OR).

The & and | operators also have two similar operators, known as conditional Boolean operators, as shown below:
1. && (var1 = var2 && var3;) var1 is true if var2 and var3 are both true or false otherwise (Logical AND) and

2. || (var1 = var2||var3;) Var1 is true if either var2 or var3 (or both) are true or false otherwise. The use of && and || aid better performance than & and | so always use && and || where possible.

Olufemi

C# Variable

2008-08-04T11:58:00.004+02:00

All Data in a computer is effectively the same thing(a series of zeros & one). Variables are of different types. Using a box analogy to explain variables; one can assume variables in computer memory as boxes sitting on a shelf. One can imagine that your boxes come in different shapes & sizes and some things will only fit in certain boxes. According to this analogy different types of data may require different methods of manipulation.

To use variables you have to declare them. This means that you have to assign them a name and a type. If this is done the variable can be used as storage units for the type of data that you declare them to hold. C# syntax for declaration of variable and type is:
(type) (name);
If any variable is not declared your code will not compile. There are certain types of data that just about everyone will want to use at one time or the other such as a variable that stores a number. There are a number of simple, predefined types that one should be aware of:

Type

sbyte
byte
short
Ushort
int
Uint
long
Ulong
float
double
decimal
char
bool
string

It should be noted that string has no upper limit on the amount of characters because it can use varying amount of memory; while boolean type bool is one of the most commonly used variable type in C#.

Example of variable declaration

1. Create a new console Application

2. Add the following code to program.cs

Static void Main(string [] args)
{
int myInteger;
string myString;
myInteger=17;
myString= "\"my Integer\" is ";
Console. writeline ("{0} {1}.", mySrting, myInteger);
console.Readkey();
}

3. Execute the code

Variable Naming
The basic variable naming rules are:

The first character of a variable name must be either a letter or underscore(_), or the at(@) symbol.
Subsequent characters may be letters, underscore characters or numbers.

e.g. myBigVar
VAR1
_test
@test

While these are wrong
99Bottlesof Beer
namespace
It's-All-Over

These are wrong because of some certain keywords that have a specialized meaning to the C# compiler such as namespace while others are number and case sensitivity.

Furthermore, one can have multiple variables whose names differ only in case, such as the ones below:
myVariable
MyVariable
MYVARIABLE

Naming Conventions
Over the years different systems have come and gone while some developers fought tooth and nail to justify their own system of naming.

Hungarian notation is recently known as the most popular system. This entails placing a lower case prefix on all variable names that identifies the type. For instance, if a variable were of type int then you might place an i (or n) in front of it such as in iAge. Adopting this system, it will be easy to see it at a glance what types different variables are.

Currently, there are two naming conventions in use in the .Net framework namespace; they are:

(a) PascalCase e.g.
Age
LastName
WinterOfDiscontent

(b) camelCase e.g.
age
firstName
timeOfDeath
For simple variable use camelCase but for advanced naming use PascalCase which is the Microsoft recommendation.

Variable Declaration & Assignment
Recall that declaration of variable entails using their type and name e.g.
int Age;
Then assign values to variable using (=) assignment operator
age=25;

Declaring multiple variables of the same type at the same time can be done uing commas to separate the variables e.g.

int xSize, ySize;
i.e. xsize and ysize are both declared as integer types.

The second method you are likely to see in assigning values to variables at the same time as declaring them can be:

int age=25;
You can also use both methods together.

int xSize=4, ySize=5;

Olufemi

Basic C# Syntax

2008-08-02T15:11:00.003+02:00

C# code is similar to that of C++ and Java. Initially the syntax can look quite confusing and is lot less like written English than some other languages. C# compilers take no notice of additional spacing in code, whether made up spaces, carriage returns or tab characters. Meaning that one have a lot of freedom in the way that on will format code; though conforming to certain rules which can make the codes easier to read.

C# code is made up of a series of statements, each of which is terminated with semicolon(;), so you don't have multiple statements on one line, but for readability's sake it is usual to add carriage return after semicolons.

C# is a block-structured language, meaning that all statements are part of a block of code. These blocks, which are represented with curly brackets({ & }), may contain any number of statements or none at all. it should noted that the curly bracket does not require semicolons.

Example 1
{

code line1, statement1;

code line2, statement2;
code line3, statement3;

    }





Another important thing often seen in C# code is comments. Comments are descriptive text to your codes in plain Language(English), which is ignored by the compiler.

The first method of signifying comment is using this symbol (*/)





Example 2

   /* This is a comment*/

The second method is using //, with this approach you can write whatever you like provided you keep to one line!





  Example 3

 //This is a different sort of comment.



The next example show case how to comment can be used on the same line with a code;



Statement; // explanation of statement.





It is pertinent to not that C# code is case sensitive. Unlike some other languages as code must be entered using the right case because using wrong case will prevent a project from compiling.





Olufemi

Kind of Application you can Design with C#

2008-08-02T13:23:00.002+02:00

C# uses the Framework and so also has no restrictions on possible applications. However, here are a few of the more common application types:

Windows Applications: These are applications, such as Microsoft Office, which have a familiar Windows look and feel about them. This is made simple by using the Windows Forms module of the .NET Framework, which is a library of controls (such as buttons, toolbars, menus, and so on) that you can use to build a Windows user interface (UI).

Web Applications: These are Web pages such as might be viewed through any Web browser. the .NET Framework includes a powerful system of generating Web content dynamically, allowing personalization, security, and much more. This system is called ASP.NET (Active Server Pages .NET), and you can use C# to create ASP.NET applications using Web Forms.

Web Services: These are a new and exciting way of creating versatile distributed applications. Using Web services you can exchange virtually any data over the Internet, using the same simple syntax regardless of the language used to create a Web service or the system that it resides on.

Any of these types may also require some form of database access, which can be achieved using the ADO.NET (Active Data Objects .NET) section of the .NET Framework. Many other resources can be drawn on, such as tools for creating networking components, outputting graphics, performing complex mathematical tasks, and so on.

Olufemi

Learning C# with me

2008-08-02T12:12:00.002+02:00

What is C#?

C#, as mentioned earlier, is one of the languages that can be used to create applications that will run in the .NET CLR. It is an evolution of the C and C++ languages and has been created by Microsoft specifically to work with the .NET platform. Because it is a recent development, the C# language has been designed with hindsight, taking into account many of the best features from other languages, while clearing up their problems.

Developing applications using C# is simpler than using C++, because the language syntax is simpler. However, C# is a powerful language, and there is little you might want to do in C++ that you can't do in C#.
At times, C# code is slightly more verbose than C++. This is a consequence of C# being a type-safe language (unlike C++).C# is just one of the languages available for .NET development, but in my opinion it is certainly the best. It has the advantage of being the only language designed from the ground up for the .NET Framework and may be the principal language used in versions of .NET that are ported to other operating systems.

To keep languages such as the .NET version of Visual Basic as similar as possible to their predecessors yet compliant with the CLR, certain features of the .NET code library are not fully supported. By contrast, C# is able to make use of every feature that the .NET Framework code library has to offer. The latest version of .NET includes several improvements to the C# language, partly in response to requests from developers, making it even more powerful.

Olufemi