Unit-1: Visual programming lecture notes (Windows Programming)

Unit-1: Visual programming lecture notes (Windows Programming) in Visual programming uploaded at P.R.Engineering college

Unit-1: Visual programming lecture notes (Windows Programming) in Visual programming at P.R.Engineering college uploaded by P.R.Engineering college Staff in lecturenotes.net

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Contents at a Glance

In Unit I - Windows Programming,  The windows programming Model – Event driven programming – GUI concepts –Overview of Windows programming – Creating and displaying the window – Message Loop – windows procedure – WM_PAINT message – WM_DESTROY message – Data types – Resources – An Introduction to GDI – Device context – Text output – Scroll Bars – Keyboard – Mouse – Menus

In Unit II - Visual Basic Programming. Visual Basic Applications – Form and properties – Variables and Constants – Variant type – Procedure scope – Main – Control statements – control arrays – Creating and using Controls – Menus and Dialogs – Programming fundamentals – Objects and instances – Debugging – Responding to mouse events – Drag and Drag drop events Responding to keyboard events – keypress, keyup, keydown events – Using grid control – Graphics controls – shape and line control – File system controls – Common dialog controls – Processing files – Accessing databases with the data controls.

In Unit III - Visual C++ Programming  Visual C++ components – Introduction to Microsoft Foundation Classes Library – Getting started with AppWizard – Class Wizard – Event handling – Keyboard and Mouse events - WM_SIZE, WM_CHAR messages - Graphics Device Interface - Pen, Brush, Colors, Fonts - Single and Multiple document interface - Reading and Writing documents - Resources – Bitmaps creation, usage of BMP and displaying a file existing as a BMP.

In Unit  IV Controls , Dialog Based Applications, controls – Animate control, image list, CRect tracker – Tree control – CtabControl – Dynamic controls – slider control – progress control – Inheriting CTreeView – CRicheditView – Modal Dialog, – Modeless Dialog – CColorDialog – CfileDialog.

In Chapter V Advanced Concepts , Domain Name System – Email – World Wide Web (HTTP) – Simple Status bars – Splitter windows and multiple views – Dynamic Link Library – Data base Management with ODBC – TCP/IP – Winsock and WinInet, – ActiveX control – creation and usage – Container class.

INTRODUCTION

The interaction between the user and a program thus becomes more intimate. Rather than the one-way cycle of information from the keyboard to the program to the video display, the user directly interacts with the objects on the display.

This unit aims to be a comprehensive source for any developer who is interested in programming for the Windows platform (Microsoft Windows 98, Microsoft Windows NT 4.0, and Windows NT 5.0). It starts at the lowest level, with the Win32 API (C and VB Classic) and then goes over to MFC (C++).

There are two prerequisites for using this material. The programs are written in the C programming language and use the native Windows application programming interfaces (APIs). Hence, the reader is assumed to have a previous knowledge of the programming languages involved. Specifically, prior knowledge in C, C++, and Visual Basic is required.

Secondly, installed the machine a 32-bit C compiler and development environment suitable for doing Windows programming (Microsoft Visual C++ 6.0).

Windows program use the event-driven programming model , in which applications respond to events by processing messages sent by the operating system. An event could be a keystroke, a mouse click, or a command for a window to repaint itself, among other things.

Microsoft Visual C++ Installation

Visual C++ comes as part of the Visual Studio development suite or as a stand-alone product. In either case, you start the installation process by running the Setup.exe file from the root directory of the CD.

NOTE: If you are using Windows NT 4.0, you will need to install the Windows NT Service Pack 3 before you can install Visual C++.

First you will be presented with a dialog box providing you with the opportunity to browse the Readme file. This file contains important information that will likely impact your development effort, so you should at least scan its contents.
 
Figure 1.1 The Visual Studio Custom Setup screen

Next, you will be presented with the user license agreement. Once you have read and accepted the user license agreement and entered your product number and user ID, you will be taken to a dialog box that presents you with setup options. At this point, choose a Custom setup and click Next.

On the screen that appears, accept the default installation location by clicking Next. The setup process will begin. Read the information screens and click Next until you arrive at the Custom Setup screen, shown in Figure 1.1. (This figure displays the Visual Studio version of this screen, which shows options to install the other products in the Visual Studio suite.)

If you already have Visual C++ installed, you’ll want to get to the maintenance dialog box that allows you to add or remove components for your current installation. You access this dialog box by selecting the Workstation option. This maintenance dialog box is identical to the setup screen, so you can use it to explore the installation options.
 
The custom setup screen appears with a default set of installation options selected, which you can change as required. A check mark next to an installation option means that the option will be installed. Many of the options are arranged in a hierarchical order. If one of the items in the Options list is selected and the Change Option button is made available, you can click it to reveal further sub-options beneath the currently selected option. OK and Cancel can be used to move up the option hierarchy, saving or discarding the changes you have made to the option selection on each screen.

If an option check box is selected but shaded, only some of its sub options are selected, meaning that only some of its options will be installed.

The following exercise shows you how to use the Custom Setup or Maintenance screen to configure your installation options:
1. In the Options list of the Custom Setup or Maintenance screen, select the Microsoft Visual C++ 6.0 option as shown in Figure 1.1.
2. Click the Change Option button.
3. In the Options list, select the VC++ Runtime Libraries option. Click the Change Option button.
4. If you would like to have the CRT library source code available, and you can spare the half-megabyte of disk space that this option requires, select the check box next to that option.
5. If you have changed any of the options that are currently displayed in the Options list and you want to save the changes, click OK to revert to the previous screen in the hierarchy. Otherwise, click Cancel to leave the options as they were.
6. When you have finished configuring the options, return to the main Custom Setup or Maintenance screen, and proceed with the installation by clicking the Continue button. To abandon the installation, click Cancel.

Completing the Installation

After you have configured your installation by selecting the appropriate options from the main and sub installation screens, you click the button labeled Continue to start installing the software. You will be prompted to reboot your computer to complete the installation. After the reboot, you will be prompted to install the version of the Microsoft Developers’ Network (MSDN) library that comes with your copy of Visual C++. You should do this, as the MSDN library is the means by which online Help and documentation are provided for Visual C++.

THE WINDOWS ENVIRONMENT

Windows is a Graphical User Interface (GUI). It uses graphics to organize the user’s workspace. User’s choose items and execute programs by pointing and clicking with a mouse. The program that run from within Windows also have a Graphical User Interface (GUI); for example, MS-Excel and MS-Word. Moreover these programs can run only within Windows. This is because Windows provides these programs with a number of built in functions and data which are not available in other environments. The functions that are provided by windows include functions with the functionality to draw text in different sizes and styles using font data. Windows provides a broad range of graphical functions for drawing lines and geometric shapes and changing color. Windows program make use of these built in functions and do not have to be coded to perform these tasks. These system defined functions that an application can call are provided by an interface known as the Application Program Interface (API) Every Windows environment has its uniqueAPI. For example, the API that Windows 95 supports (also called the Win32 interface) is a 32-bit API. All the functions supported by the API can work with 32 bits of information at any given time. Writing programs for the Windows environment using the API functions is referred to as SDK programming where SDK stands for Software Development Kit.

THE WINDOWS PROGRAMMING MODEL – EVENT DRIVEN PROGRAMMING

Programs written for traditional operating environments use a procedural programming model in which programs execute from top to bottom in an orderly fashion. The path taken from start to finish may vary with each invocation of the program depending on the input it receives or the conditions under which it is run, but the path remains fairly predictable. In a C program, execution begins with the first line in the function named main and ends when main returns. In between, main might call other functions and these functions might call even more functions, but ultimately it is the program—not the operating system—that determines what gets called and when.

Windows programs operate differently. They use the event-driven programming model illustrated in Figure 1.2, in which applications respond to events by processing messages sent by the operating system. An event could be a keystroke, a mouse click, or a command for a window to repaint itself, among other things. The entry point for a Windows program is a function named WinMain, but most of the action takes place in a function known as the window procedure. 
 
The window procedure processes messages sent to the window. WinMain creates that window and then enters a message loop, alternately retrieving messages and dispatching them to the window procedure. Messages wait in a message queue until they are retrieved. A typical Windows application performs the bulk of its processing in response to the messages it receives, and in between messages, it does little except wait for the next message to arrive.

The message loop ends when a WM_QUIT message is retrieved from the message queue, signaling that it’s time for the application to end. This message usually appears because the user selected Exit from the File menu, clicked the close button (the small button with an X in the window’s upper right corner), or selected Close from the window’s system menu. When the message loop ends, WinMain returns and the application terminates.

The window procedure typically calls other functions to help process the messages it receives. It can call functions local to the application, or it can callAPI functions provided by Windows. API functions are contained in special modules known as dynamic-link libraries, or DLLs. The Win32API includes hundreds of functions that an application can call to perform various tasks such as creating a window, drawing a line, and performing file input and output. In C, the window procedure is typically implemented as a monolithic function containing a large switch statement with cases for individual messages. The code provided to process a particular message is known as a message handler. Messages that an application doesn’t process are passed on to an API function named DefWindowProc, which provides default responses to unprocessed messages.

Messages

Windows defines hundreds of different message types. Most messages have names that begin with the letters “WM” and an underscore, as in WM_CREATE and WM_PAINT. These messages can be classified in various ways, but for the moment classification is not nearly as important as realizing the critical role messages play in the operation of an application. The following table shows 10 of the most common messages. Awindow receives a WM_PAINT message, for example, when its interior needs repainting. One way to characterize a Windows program is to think of it as a collection of message handlers. To a large extent, it is a program’s unique way of responding to messages that gives it its personality.
 
A message manifests itself in the form of a call to a window’s window procedure. Bundled with the call are four input parameters: the handle of the window to which the message is directed, a message ID, and two 32-bit parameters known as wParam and lParam. The window handle is a 32-bit value that uniquely identifies a window. Internally, the value references a data structure in which Windows stores relevant information about the window such as its size, style, and location on the screen. The message ID is a numeric value that identifies the message type: WM_CREATE, WM_PAINT, and so on. wParam and lParam contain information specific to the message type.

Title:
Unit-1: Visual programming lecture notes (Windows Programming)

Subject:
Visual programming

Institute:
P.R.Engineering college

Unit-1: Visual programming lecture notes (Windows Programming)

Unit-1: Visual programming lecture notes (Windows Programming) in Visual programming uploaded at P.R.Engineering college

Summary / document preview text:

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