Vb help pdf

Cannot be accessed by other classes. A class can be made as a user defined data type. An Object becomes a variable of type class. It is the most striking feature of class. The data of a class not access able to outside and functions which are wrapped inside a class can only access it.

This is called data hiding. It means the ability to take more than one form. The same operation can also add two strings which produce the third string.

So, this concept says that a single operation can be used to handle different types of tasks. In this diagram a single function namely draw can be used to handle different actions such as drawing a box, rectangle and circle. Dynamic Binding means code will be executed response to the procedure call only at run time.

There fore a message for an Object is request for execution of the procedure. Message communication is specified by specifying name of the Object, name of the procedure and the information. EX: - Employee salary Basic : Object name message information OR Function 9 Abstraction: Abstraction refers to out of the representing essential figure with out including back ground details.

Abstraction focuses on the essential aspects of an Object and ignoring its accidental properties. In system development these means focusing on what an Object is and does before deciding how it should be implemented. Since classes used the concept of data abstraction they are known as Abstract data types.

The new technology promises greater productivity better quality and lesser maintains cost. This lead to saving of development time. Applications of OOPS are beginning to gain importance in many area. The most popular application of OOP, up to now has been in the area of user interface design such as windows. There are hundreds of windowing systems developed using OOP techniques.

Real business systems are much more complex and contain many more Objects with complicated attributes and methods. OOP is useful in this type of applications, because it can simplify a complex problem. The data items are global.

The data items are capsule into Object. Program flow control is through jump 2. Different control construction is available Statement and call of the procedure and by 3.

No data security is available. No user defined data type available. Data security is provided by encapsulating the data into Object and a massage passing 5. Functions are independent of data. Modularity is available through program Modularity by dividing into procedure 4. The abstract data types are introduced. Enhancement of program is very difficult. High modularity is available by dividing the Modularity by dividing into procedure.

Even maintain of the program is very Program into the modules and further modules into classes and Objects. Program is algorithm depending. Best suitable for large application. The application may enhance easily. Even large application can be maintained Difficult. Easily because of high modularity. Program is data depending. The basic parts refer to the basic language because all the statement of basic language is used in visual basics. However VB contains its own functions, methods, controls etc.

Visual Basic version 6. VB 6 provides graphical environment in which forms basic blocks of application. Using VB 6 users can create windows based application. VB 6 provides many advanced tools such as templates, data based management, Objects classes.

Using these tools applications can be developed with in days or months. This edition includes all the advanced tools use to develop Active X controls and internet tools. Features of VB: When ever product version number is increase by one it means that some development as been made to the previous version.

Here development means more advanced features are add to previous version. Some of the general and advanced features of VB are as follows: 1 General features: The compiler in VB 6 gives many different options for optimizing the compiled code.

VB 6 is open environment that supports client and server architecture, Active X. This feature includes: a. Quick information: This feature presents the syntax of the procedure. Complete word: Complete the word automatically after typing some few characters of the word. Data tips: This is a very useful feature that shows the value of a variable in yellow tool tips.

List members: List all the properties or methods available to a given Object. List Constance: List Constance values for a given property.

Data environment: This feature provides an interactive design time environment. This environment can be used to design forms and reports which form the basic blocks of application. Data report: This feature allows to create report. Each grid contains its own record set. Server always responds user request. Controls accepts input and also displays output.

All the controls in VB have their own properties, methods and events. Controls add function to your application. To each control we can write code to make them active.

The toolbox is the window that contains all the controls required for the application we can develop our own controls and add them to the tool box Adding controls: Controls are added to you form in two ways by double clicking by dragging.

Whenever you double click on a control present in the toolbox. It can be seen on the form. Select the control drag and place it on the form then the associated control can be seen on the form.

Removing a control: 1 Select the control which you want to remove by clicking on it. Size and positioning a control: To increase or decrease the size of a control. Hold the pointer with mouse without releasing and drag to required size now release the mouse.

Interface Elements or Standard Controls: Interface elements are automatically displayed in the tool box once a form is loaded. All this interface elements are very powerful.

Some of the interface elements available on the tool ox are as follows. It behaves like mine edition. This also takes two values true or false. Events are recognized by various controls but are handled by the application code. The code that is provided to the control can be called as a sub routine. The sub routine determines how a control reacts to an event so it is called as an event handler to write an event handler for a control, follow the below steps: 1 Switch to the code window by selecting particular control and press F7.

The combination of control name and events name specifies that the user is going to write an event handler for a particular control. The code inside a control will never execute if the event takes place the quality makes visual basic a very responsive system.

A few common events: - 1 Mouse events: - a click, double click: Click event takes place when the user clicks the left mouse button. The double click events take place when the user double clicks the mouse button. Mouse up event takes place when the mouse left button is released. Key up events takes place when the key is released. You can use got focus event for editing. You can use lost focus event to validate the data entered by the user.

You can also move from one control to another control using set focus method. Methods are the actions that the Object can carry out. In other words methods are the action of an Object. For example: - The methods of VCR are play, rewind fast forward etc. If the control is a list box then clear method removes all times from the list box. For example: - To add item in the text box namely countries.

Example: - Countries. To apply a method to a control simply just write the name of the control followed by a dot. A form is a top level Object in visual basic every application developed in VB starts with form when a VB application is executing each window is a form. To the right end of the title bar there are three buttons minimize, maximize and close the control menu contains the following commands. Form Methods: A form cans the in one of following states.

Show methods: Show methods of form bring the specified form on the screen. Models Form: A models form takes allows the user to choose any form without closing it. If you do not specifies the value for made option, then the show method displays the form as modeless.

Hide method: This method removes a form from the screen but does not unload it. The general syntax is form name wide , when a form is hidden a user control interact with it. Events of form: - 1 activate: - This event occurs when the form becomes the active window. A form will become in active when the user switches his focus to some other form either by clicking or by using show methods or set focus method.

A form will become inactive when the user switches his focus to some other form. The code that is present under this event generally include initialization code for a form default setting for controls, contents to be loaded into combo box or list box.

Setting Form Properties: Event Object in VB has its own properties since a form is also a top level Object it has its own properties to set properties to a specific form follow the steps. It means it can be set at run time and not yet design time.

Important properties of forms: - 1 Window property: - This property is responsible when the form starts up it has three options. They are 0-normal this will open the form in normal state. But it effects the color of text you point on the form. When you double click on this property colour palates is opens from which you can select the required colors 6 Width property: - Changes the width of the form. This is also set by dragging forms borders in design view.

You can also set the height by dragging forms borders in design view. If settled to false users cannot maximize the form. If set to false users cannot minimize the forms. It will become invisible along with this three buttons in the right of the title bar also become invisible. Font bold: - It takes Boolean values and sets bold font.

Font Italic: - It takes Boolean values and sets italic font style. Font name: - Sets the specified font. Font size: - Sets the size of the font. Font underline: - Underlines the font. Font strike threw: - Strikes the font with a line. Border style property: - This property sets the style of the forms borders.

This property can take one of the following values. This property is useful if there are twenty to thirty forms in your application. Circle x, as single, y, as single, x2 as single End Sub Set: sets the pixel on an Object. Cls End sub. Integrated Development environment: IDE is a term commonly used in programming world. It stands for integrated development environment. This word describes the interface and environment used to create applications. It is called integrated because you can access all the development tools needed for one screen.

Visual basic is not just a language but also provides an IDE in which you can develop run, test and debug your applications. Once you start VB you will see, a window which will ask you to select type of project. Project: A project is an application which you develop using IDE. The different types of projects you can develop are: 1 Standard EXE: A standard exe project is a typical application. Most of the projects developed in VB are standard exe projects.

This two types of projects are identical in functionality but are packed differently. Use this type of projects to develop your own active x controls. Menu bar: Menu bar contains the command use full to work with VB. The basic a menus available in the menu bar are a. File menu: It contains commands for opening and saving projects. It also contains commands for listing recent projects and for creating executable files. Edit menu: It contains commands like undo, copy, cut, paste, redo…..

View menu: Contains commands for showing or hiding components of IDE. Project menu: Contains commands that add components to the current project. Format menu: Contains commands for aligning the controls on the form.

Run menu: Contains the start, break, end, application commands. Debug menu: Contains debugging commands. Tools: Contains tools which are helped in building active x components. Help: Contains information which will help you to work with VB. Tool bar types: Tool bar gives quick access to menu commands. To open and close toolbars. Choose view tool bars. Project Explorer: The window titled as project is the project explorer, which displays the components of the project. Tool bar: Toolbar contains icons of the control.

The can be placed on a form to create an application. To place a control first selects it with the mouse over the Form. Instead of crowding a tool box with all the controls you need for a project you can create several tabs with icons o tool box and organize the controls according to them. To add a new tab to the tool box follow the steps.

Right click on the tool box to open the pop up menu 2. VB displays a new tab button on the tool box. Selected the components option and VB displays a list of all active x controls installed on your system. To add the required active x controls to the tab check big in front of the names f the control. Form designer: The form designer is the main window which appears in the middle of the screen and in it you can design and edit the application. The same window displays a text editor in which you can enter the application code so the form designer tool displays two windows.

The Form Window 2. The Code Window To switch between the two windows choose an icon in the project explorer namely view code to open the code window or choose view Object to open the specified form. Properties window: Properties window to contain a set of properties for the selected Object or controls properties are the character sticks of an Object such as its size, caption, color and soon you can open the properties window for a particular Object by selecting it and choosing view properties from the menu bar.

You can also change the appearance of the Object on the form through properties window. Properties can be Object characteristics or attributes every Object in the tool box has their own properties. A property for an Object can be set either at design time or at run time. To set the properties at run time we generally use dot notations. The general form of dot notation Object name property name value. If it is string enclose it with in quotation. For example: Form 1.

It cannot be set at run time some properties are available only at run time. To set property at design time press F4 keys after selecting the Object. Some of the common properties in every Object available are: 1 Name: - It set the Object name through which the Object can be manipulated. These values determine whether user can manipulate the Object or not. This value determines whether user can see the Object or not. Object browser window: Object browser allows the user to browse through various methods, events, properties, that are available for a particular Object.

You can access Object browser from view menu or by pressing F2 key Object browser provides the following information on both in Objects and custom Objects 1. Classes 2. Methods 3. Events 4. Properties 5. Constant values Components of Object browser: 1. EX: you must choose word project from the project library drop don list which immediately displays all the Objects of that project.

Class list: It shows the available classes for the project selected in project library drop down list. Members of list: Displays the available numbers for the class list that is method, constants, events, properties are the members of the class list. Search text box: In this text box enter the string you want to search for. Show definition button: Click this button to display code window for the Object selected in the class list. Navigating with Object browser: a. First activate the Object browser by selecting view Object browser from the menu bar or press F2 key.

In the project library drop down list select the name of the project that you want to view. In the class list select the class you to work with. If you want to work with a particular member of the class select in the members of the list. You can view the information about the member selected at the button of the browser window. Its purpose is to simply give the user model i.

This window is also useful for knowing how the form looks when your application is running. To open the form layout window choose, view form layout window from the menu bar.

Once the form layout window is opened click the form in the form layout window and move it to the center. You can examine or change the values of the application variables. It is one of the reasons for the popularity of VB. It let you to step into the application code change the value of the variables and even insert statements in the code and then continue the execution application.

Customizing the tool bar: One of the main features in the IDE is the availability of the tool bars. If you are really confused with all tool bars you can customize these tool bars as follows. Moving a toolbox button: If you want to move some buttons on the toolbar. Follow these steps: 1 Right click the menu bar or tool bar at the top of the screen.

Removing and Adding a menu item: If the tool bar does not contain short cuts you want, then you customize them further to get what you want, 1 Right click the menu bar or tool bar at the top of the screen. In this tab you have two flames.

Code setting frame: it contains the options that will effect your code window editor. This option is: a Auto list members: Check this check box to display a list of members methods, properties belonging to an Object. This if you prefer to see one procedure in the editor at a time. You can set grid lines using form grid setting frame. You this line to align the control on the form. Error trapping selection allows to set error trapping i.

Compile sections contains the following options. Set compile on demand. Enable back ground compile allow you to continue working in VB while it compile your applications, this setting is enabled by fault. Checking show tool tips allow VB to show you tool tips that describe the control. Docking tab: By selecting the clocking tab you can determine which windows with in IDE are docks able.

The environment tab: The environment tab is the most important place to customize settings with in IDE. When you are involved in serious project developments you want to save your work often. To do this to check the promote to save changes option. The advanced tab: 1. Selecting the back ground project load options will force VB to load projects while you continue working. This is useful because it allows you to continue working while a project loads.

Leave the notify when changing shared project items option checked. A variable has a name and a value when a variable has a text value it should be enclosed with in quotations.

Example: - Dim name as string. Dim meters as integer. In VB having two type of declarations. They are Explicit and Implicit Declarations. You can declare multiple variable of same type i. Dim a, b, c as integer. So, what data type is declared we have to enter the same type of data. That means variable type is variant. In such case VB can assigns run type of data can be assigned at runtime.

They are: 1 Integer and long 2 Single and double 3 Integer and long Any variables declared as integer or long stores whole numbers. Example: Dim a as integer Dim b as long Single and double: variables declared as single or double stores fractional numbers. Double gives the accurate results compared to single.

Example: Dim x as single Dim y as double 2 String variables: String data type stores only text and its value is enclosed with in quotations. Example: Dim var name as string. Example: Dim var name as byte This data type is generally used to store images or sounds etc. It is declared using the word Boolean. Example: Dim var name as Boolean. Any variable Declare as variant is handle by VB according to the variables constants. If you assign a string value, VB treats it as an integer.

If you assign a string value, VB treats it as a string. Its type depends on the contents you can also specify variant type to make the code clear. You would use the full Acrobat product in about the same way that other object libraries, like Word above, are used. I don't happen to have the full Acrobat product installed so I couldn't provide any tested examples here.

NET Toolbox. It will do the job for free. To use the Reader control, first make sure that you have downloaded and installed the free Acrobat Reader from Adobe. Step 2 is to add the control to the VB. Open VB. NET and start a standard Windows application. Microsoft's "next generation" of presentation, WPF, doesn't work with this control yet.

To do that, right-click on any tab such as "Common Controls" and select "Choose Items Now just drag the control to your Windows Form in the design window and size it appropriately. For this quick example, I'm not going to add any other logic, but the control has lots of flexibility that I'll tell you how to find out about later. To do that, add this code to the form Load event procedure:.

Substitute the path and file name of a PDF file on your own computer to run this code. I displayed the result of the call in the Output windows only to show how that works. Here's the result:. If you want to control the Reader, there are methods and properties for that in the control too. But the good folks at Adobe have done a better job than I could.

If you don't have the full Acrobat system installed - which must be purchased from Adobe - you won't be able to run other examples. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Best Practices to Use Visual Basic 6. NET Together. A Microsoft Visual Basic 6. NET class libraries, but to do so, it must go through an interoperability layer, known as a client callable wrapper.

This wraps the desired. Learn how to create these wrappers. Best of all, it is completely free, and can be redistributed with your application. Calling Web Services from Visual Basic 6. This article shows you how to build an application that downloads satellite photos of a given street address from Visual Basic 6. This article, the first in a four-part series, shows that it is not necessary to migrate a Microsoft Visual Basic 6. NET in order to take advantage of. NET functionality.

Enhancing a Visual Basic 6. This article, the second in a four-part series, demonstrates how to use. This article, the third in a four-part series, shows how to include modern, simple-to-configure Microsoft Visual Basic. This article shows how you can add automatic updating functionality to your existing Visual Basic 6.

NET Framework 2. Deploying the Hybrid Visual Basic 6. NET Application. This article—the last in a four-part series that walks through enhancing an existing Microsoft Visual Basic 6.

This article examines the functionality provided by the. Using Background Threads with Visual Basic 6. Learn how to use the. This article shows you how to inform the user of progress, how to allow the user to cancel the background task, and how to debug multi-threaded applications. NET Framework - Part 1. NET Framework. NET Framework - Part 2. This article explains how you can use Visual Basic 6 with the.

Accessing the Event Log from Visual Basic 6. Instrument your applications so that other people can look at the event logs to diagnose issues from Visual Basic 6. Access the File System with. Accessing the file system is a common application requirement, and in the spirit of Microsoft Visual Basic Fusion, this article shows how to access some of the best Microsoft. Learn how to get the extension for a file, the directory portion or a path, or the file name portion of a path.

Learn how to fire events every time the contents of a directory change. While Microsoft no longer ships a migration wizard, our partners offer migration tools and solutions. Here are more resources to help answer questions on how to migrate from Visual Basic 6.

The first step in a phased migration to. NET is to assess which upgrade strategy is right for you in order to come up with a migration plan.