The InternetWritten by Varuna Sood
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LANs were used for administrative, educational and research purposes.Libraries used LANs to hold their catalogs.In time, university research LANs and commercial LANs could share information. Eventually, commercial networks were created for sole purpose of giving consumers access to this rapidly expanding infrastructure, this Internet, of computer-based communication. The Internet now reaches into more than 185 countries, connects more that seventy thousand computer networks , ansd is used by over three hundred million people worlwide.
Varuna Sood B.Tech Computers India
Introduction to Visual BasicWritten by Pawan Bangar
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Stopping Visual Basic
You'll exit from Visual Basic and return to Windows same way you exit most Windows applications: Select File|Exit, click Visual Basic's main window close button, press Alt+F4, or double-click VB's Control menu icon that appears in upper-left corner of screen. If you have made changes to one or more files within currently open project (remember that a project is collection of files that comprise your application), Visual Basic gives you one last chance to save your work before quitting to Windows. Mastering Development Environment Learning ins and outs of development environment before you learn Visual Basic is somewhat like learning parts of an automobile before you learn to drive; you might have a tendency to skip terms and jump into foray. If, however, you take time to learn some of development environment's more fundamental principles, you will be better able to learn Visual Basic. You then will be more comfortable within VB's environment and will have a better understanding of related words when subsequent lessons refer to windows and tools in development environment.
Standards: The Menu Bar and Toolbar Visual Basic's menu bar and toolbars work just as you expect them to. You can click or press a menu bar option's hotkey (for example, Alt+F displays File menu) to see a pull-down list of menu options that provides either commands, another level of menus, or dialog boxes. Many of menu options have shortcut keys (often called accelerator keys) such as Ctrl+S for File|Save option. When you press an accelerator key, you don't first have to display menu to access option. The toolbar provides one-button access to many common menu commands. Instead of selecting Edit|Paste, for example, you could click Paste toolbar button. As with most of today's Windows applications, Visual Basic supports a wide range of toolbars. Select View|Toolbars to see a list of available toolbars. Each one that is currently showing will appear with a checkmark by its name. The Form Window: Where It All Happens The Form window is your primary work area. Although Form window first appears small relative to rest of your screen, Form window comprises background of your application. In other words, if you write a Windows-based calculator with Visual Basic, calculator's buttons all reside on Form window and when someone runs calculator, calculator that appears is really just application's Form window with components placed there and tied together with code. Source program is code, forms, menus, graphics, and help files that you create and edit to form project (also called source code). The parts of application that you create, such as forms, code, and graphics that you prepare for output, comprise source program. When you or another user compiles or runs source program, VB translates program into an executable program. You cannot make changes directly to an executable program. If you see bugs when you run program, you must change source application (which might contain multiple files in project) and rerun or recompile source. The Toolbox Supplies Controls The toolbox contains controls that you place on Form window. The toolbox never runs out of controls; if you place a command button on Form window, another awaits you on toolbox, ready to be placed also. The Form Layout Window Places Forms The Form Layout window displays initial position and relative size of current form shown in Form window. The Form Layout window always shows where form appears in current Form window. If you want form to appear at a different location from current position, you can move form inside Form Layout window to move form's appearing position when user runs application. The Project Explorer Window The Project Explorer window, often called Project window, gives you a tree-structured view of all files in application. Microsoft changed formal name from Project window to Project Explorer window between versions 4 and 5 to celebrate resemblance of window to typical Explorer-like tree-structured file views so prevalent in Windows 95 and NT. You can expand and collapse branches of view to get more or less detail. The Project Explorer window displays forms, modules (files that hold supporting code for application), classes (advanced modules), and more. When you want to work with a particular part of loaded application, double-click component in Project window to bring that component into focus. In other words, if Project Explorer window displays three forms and you need to edit one of forms, locate and double-click form name in Project window to activate that form in Form window. The Properties Window A different list appears in Properties window every time you click over a different Form window tool. The Properties window describes properties (descriptive and functional information) about form and its controls. Many properties exist for almost every object in Visual Basic. The Properties window lists all properties of Form window's selected control. Help Is at Your Fingertips Visual Basic's online help system is one of most advanced on market. When you want help with a control, window, tool, or command, press F1. Visual Basic analyzes what you are doing and offers help. In addition, Visual Basic supports a tremendous help resource called Books Online. When you select Books Online from Help menu, Visual Basic displays a tree-structured view of books about Visual Basic that you can search and read. The online help extends to Internet as well. If you have an Internet connection, you can browse latest help topics by selecting Help|Microsoft on Web. Summary Perhaps you already can see that Visual Basic is more than it first appears. Programmers use Visual Basic to create extremely advanced Windows applications.
Pawan Bangar. Technical Director. Ebirbals. India.