In software engineering, a class diagram in the Unified Modeling Language (UML), is a type of static structure diagram that describes the structure of a system by showing the system's classes, their attributes, and the relationships between the classes.
The UML specifies two types of scope for members: instance and classifier[1]. In the case of instance members, the scope is a specific instance. For attributes, it means that its value can vary between instances. For methods, it means that its invocation affects the instance state, in other words, affects the instance attributes. Otherwise, in the classifier member, the scope is the class. For attributes, it means that its value is equal for all instances. For methods, it means that its invocation do not affect the instance state. Classifier members are commonly recognized as "static" in many programming languages. To indicate that a member has the classifier scope, its name must be underlined. Otherwise, as default, the instance scope is considered.
Monday, June 15, 2009
OpenFileDialog
Prompts the user to open a file. This class cannot be inherited
This class allows you to check whether a file exists and to open it. The show read only property determines whether a read-only check box appears in the dialog box. The ReadOnlyChecked property indicates whether the read-only check box is checked.
Most of the functionality for this class is found in the FileDialog class.
If you want to give the user the ability to select a folder instead of a file, use FolderBrowserDialog instead. The following code example creates an OpenFileDialog, sets several properties, and displays the dialog box using the CommonDialog..::.ShowDialog method. The example requires a form with a Button placed on it and the System.IO namespace added to it.
This class allows you to check whether a file exists and to open it. The show read only property determines whether a read-only check box appears in the dialog box. The ReadOnlyChecked property indicates whether the read-only check box is checked.
Most of the functionality for this class is found in the FileDialog class.
If you want to give the user the ability to select a folder instead of a file, use FolderBrowserDialog instead. The following code example creates an OpenFileDialog, sets several properties, and displays the dialog box using the CommonDialog..::.ShowDialog method. The example requires a form with a Button placed on it and the System.IO namespace added to it.
Monday, March 23, 2009
Cats and Dogs =D
Today in VB, we had to make our own classes and properties. To make it easier to understand, it was realted to a cat and a dog, two physical things with very obvious properties(name, furcolour etc) and actions, like meowing or going for 'walkies'.
I thought it was really interesting, still confusing for me now, but with a little more exploration i'll hopefully understand it better. From what I could gather, it opens an extreme amount of doors for programming things with-in VB, and add's another complex level to it. Heh.
First of all, with in the Dog Class;
It had properties and methods. The properties were the things it has, like a name, age and a breed. And it's methods are like barking and going for walkies
With the dog class, it has similar properties, but its methods were different, having meow and chase mouse functions.
I thought it was really interesting, still confusing for me now, but with a little more exploration i'll hopefully understand it better. From what I could gather, it opens an extreme amount of doors for programming things with-in VB, and add's another complex level to it. Heh.
First of all, with in the Dog Class;
It had properties and methods. The properties were the things it has, like a name, age and a breed. And it's methods are like barking and going for walkies
With the dog class, it has similar properties, but its methods were different, having meow and chase mouse functions.
VB Classes and Objects
In VB.NET, a class is that chunk of code mentioned earlier. You've been using Classes all the time during this course. The Form you've started out with is a Class. If you look right at the top of the code window for a Form, you'll see:
Public Class Form1
The word "Public" means that other code can see it. Form1 is the name of the Class
If you look at the bottom of the coding window, you'll see End Class, signifying the end of the code for the Class.
When you place a Button or a textbox on the Form, you're really adding it to the Form Class.
When you start the Form, VB does something called instantiation. This basically means that your Form is being turned into an Object, and all the things needed for the creation of the Form are being set up for you (Your controls are being added, variables are being set up an initialised, etc).
And that's the basic difference between a Class and an Object: A Class is the code itself; the code becomes an Object when you start using it.
Public Class Form1
The word "Public" means that other code can see it. Form1 is the name of the Class
If you look at the bottom of the coding window, you'll see End Class, signifying the end of the code for the Class.
When you place a Button or a textbox on the Form, you're really adding it to the Form Class.
When you start the Form, VB does something called instantiation. This basically means that your Form is being turned into an Object, and all the things needed for the creation of the Form are being set up for you (Your controls are being added, variables are being set up an initialised, etc).
And that's the basic difference between a Class and an Object: A Class is the code itself; the code becomes an Object when you start using it.
Monday, March 9, 2009
ASCII
Historically, ASCII developed from telegraphic codes. Its first commercial use was as a seven-bit teleprinter code promoted by Bell data services. Work on ASCII formally began October 6, 1960, with the first meeting of the American Standards Association's (ASA) X3.2 subcommittee. The first edition of the standard was published in 1963, a major revision in 1967,and the most recent update in 1986.Compared to earlier telegraph codes, the proposed Bell code and ASCII were both ordered for more convenient sorting (i.e., alphabetization) of lists, and added features for devices other than teleprinters.
ASCII includes definitions for 128 characters: 33 are non-printing, mostly-obsolete control characters that affect how text is processed; 94 are printable characters, and the space is considered an invisible graphic.The ASCII character-encoding scheme is the most-commonly-used character set on the Internet
Unicode is a computing industry standard allowing computers to consistently represent and manipulate text expressed in most of the world's writing systems. Developed in tandem with the Universal Character Set standard and published in book form as The Unicode Standard, Unicode consists of a repertoire of more than 100,000 characters, a set of code charts for visual reference, an encoding methodology and set of standard character encodings, an enumeration of character properties such as upper and lower case, a set of reference data computer files, and a number of related items, such as character properties, rules for normalization, decomposition, collation, rendering and bidirectional display order (for the correct display of text containing both right-to-left scripts, such as Arabic or Hebrew, and left-to-right scripts).[1]
The Unicode Consortium, the non-profit organization that coordinates Unicode's development, has the ambitious goal of eventually replacing existing character encoding schemes with Unicode and its standard Unicode Transformation Format (UTF) schemes, as many of the existing schemes are limited in size and scope and are incompatible with multilingual environments.
Unicode's success at unifying character sets has led to its widespread and predominant use in the internationalization and localization of computer software. The standard has been implemented in many recent technologies, including XML, the Java programming language, the Microsoft .NET Framework and modern operating systems.
Unicode can be implemented by different character encodings. The most commonly used encodings are UTF-8 (which uses 1 byte for all ASCII characters, which have the same code values as in the standard ASCII encoding, and up to 4 bytes for other characters), the now-obsolete UCS-2 (which uses 2 bytes for all characters, but does not include every character in the Unicode standard), and UTF-16 (which extends UCS-2, using 4 bytes to encode characters missing from UCS-2).
The Unicode Consortium, the non-profit organization that coordinates Unicode's development, has the ambitious goal of eventually replacing existing character encoding schemes with Unicode and its standard Unicode Transformation Format (UTF) schemes, as many of the existing schemes are limited in size and scope and are incompatible with multilingual environments.
Unicode's success at unifying character sets has led to its widespread and predominant use in the internationalization and localization of computer software. The standard has been implemented in many recent technologies, including XML, the Java programming language, the Microsoft .NET Framework and modern operating systems.
Unicode can be implemented by different character encodings. The most commonly used encodings are UTF-8 (which uses 1 byte for all ASCII characters, which have the same code values as in the standard ASCII encoding, and up to 4 bytes for other characters), the now-obsolete UCS-2 (which uses 2 bytes for all characters, but does not include every character in the Unicode standard), and UTF-16 (which extends UCS-2, using 4 bytes to encode characters missing from UCS-2).
Sunday, February 15, 2009
Two Visual Basic sites, that I believe are awesome =)
Visual Basic 2008 is an evolution of the Visual Basic language that is engineered for productively building type-safe and object-oriented applications. Visual Basic enables developers to target Windows, Web, and mobile devices.
The first site is:
And the second site of awesomeness is:
Welcome to my lair!
BWAHAHAHAHA! Not sure if I was meant to post somthing or not but ... I did anyway ... WELCOME ... and now you may never leave so join me in an eternal tea party =D We have cookies~
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