Note on visual basic pdf

Add the buttons that you want. Supply the caption, the key to access the button, etc. The Key that you give here will be the reference you will use when you want to send the toolbar events to menu items.

Picture : View the picture of the icons selected. Multiple document Interface: The MDI was designed to simplify the exchange of information among documents, all under the same roof. With a MDI application, you can maintain multiple windows, but not multiple copies of the application.

Data exchange is easier when you can view and compare many documents simultaneously. The main form or MDI form is not duplicated, but it acts as a container for all the windows, and it is called the parent window. A MDI application must have at least two forms, the parent form and one or more child forms. There can be many child forms, but only one parent form.

He parent form may not contain controls. While the parent form is open in the design mode, though the icons in the toolbox are not disabled, but you cannot place any control on the form. But you can place controls in child forms. To create a MDI application follow these steps: 1. Make this form child by setting its MDIChild property true. To denote that this is a child form set its caption to MDIChild. Double-click your picture control in the tool box.

It will appear as toolbar to your MDI form. Place three command buttons on this toolbar and change their names and captions to newchild, cascade and tile respectively. The MDI window will look as in the below. Enter the codes as shown in the below. Save and run the project.

See how you can arrange the child windows in tiles or cascades. You cannadd any number of child windows by clicking the newchild button. A typical tile arrangement of child windows is shown in the below and cascade arrangement of the child windows in the below. To create an MDI application 1. Create an MDI form. Note An application can have only one MDI form. If no code in these QueryUnload event procedures cancels the Unload event, then each child is unloaded, and finally the MDI form is unloaded.

Because the QueryUnload event is invoked before a form is unloaded, you can give the user the opportunity to save a form before unloading it. Features of MDI Form? In order to display as many documents as the user wants, your application will have to replicate itself as many times. If this were possible, imagine the number of controls, and the code that would have to be loaded in memory.

There must be a more practical and efficient way to solve this problem. It is in the form of the Multiple Document Interface MDI 1 An MDI application allows the user to display multiple documents at the same time, with each document displayed in its own window. Documents or child windows are contained in a parent window, which provides a workspace for all the child windows in the application.

The user can start an application, minimize it and close it with a single control , need not close all the Forms. After all functions like adding, displaying, sorting records, etc. Common controls can be available with the MDI form and share by the other forms.

Building User Interface The principles of design that is applicable in most interactive systems. These underlying principles of interface design Consistency:- Visual Basic offers a host of controls, However, do not make the mistake of using all of them. A number of controls can be used to do the same job.

For a particular task have to use the particular control only. Fonts :- The fonts are another area where the designer might run away with his imagination. Simplicity :- Make sure that the interface you present to the user is simple and easy to use. The interface is the place where you show a concern for the user who is not as knowledgeable about computers as you are. It must be based on the thought pattern of an Average user.

Try and think how the target user will accomplish this job. Provide clues where required without making an overkill. Usability :- The user must be able to use your application with ease.

The user is also concerned with the help ,hints and guidance he can get from the applications itself. Images :- A picture is worth a thousand words. Your understanding of the theme will depend upon your frame of mind at the time.

That is the problem of using images or icons to convey a message. Use only those pictures and icons in your program that are universally understood and accepted. What you understand may not be what the user does.

Colors :- Use Simple colors. The user is going to be looking at the form that you have designed. Do not have too many colors on your form. When viewed on a color display, some of the colors may disappear.

Compile Time Errors 2. Runtime Errors 3. Logic Errors 1. Compile Time Errors: These Errors occurs while writing the code. They usually occur when the syntax of any visual basic statement is invalid. These Errors are easy to locate and correct.

VB checks the syntax of each line of code as you enter and informs you by means of highlighted text. They do not occur until you run your application. Logic Errors: Logical Errors occur when your application produces in correct results. These errors normally occur due to a mistake made by the programmers. Error Description Syntax Error Occurs when we enter an incorrect line of code such as a mistake in typing a keyword, a punctuation is missing or an incorrectly spelled variable.

For example, using an If statement without a matching End If results in a syntax error. Visual Basic notifies us of the syntax errors before we leave a line of code. Run-time Error Occurs when a command attempts to perform an action that is not valid.

For example, a run-time error occurs if we try to assign a string to a numeric variable. Error handlers execute only if a run-time error is encountered. Logic Errors Occurs when an application executes without syntax errors or run-time errors, but the results are not what we intend. For example, an application might prompt the user for a password but then may not allow access to the application even if the password is correct. This might be acceptable during development and testing phases. So, your code should trap and deal with its own errors.

This statement waits for an error to occur and when the error occurs the error trap statement performs an action written under error handler. On error statement has three forms. On Error Goto Label 2. On Error Resumenext 3. On Error Goto 1. On Error Goto Label : using this statement in your code, makes VB application to jump to a specific location in your code, if an Error occurs. Errors handle code is always written at the end of the procedure.

This is because in the code, If no error occurs, you must exit the procedure, before reaching the error handler. Otherwise VB executes Error Handling code. On Error Resume Next : It tells VB application to suppress the standard error message and simply execute the next line of code. If the file exist the kill procedure deletes it.

But, it is suppressed due to an error resume next statement and procedure terminates normally. This has a number of properties. The most important properties are number and description. Property Description Number Returns or sets a numeric value specifying an error. We use the Number property to determine which error occurred. The value of the property is a unique number that corresponds to the error condition.

Syntax: Object. Number Description Returns or sets an expression containing a descriptive string associated with an error. ActiveX Components. But some Objects in windows environment are not unique to Visual Basic and they do not come with visual basic language.

So, other applications provide these Objects and use them with in you applications. OLE Enables to access the functionality of multiple applications, with in single programming environment.

OLE is not a programming technique but it is a technology provided only in windows environment. OLE Terminology: 1. A Component is an Item a control or an application that some one else has developed. Compound Document: A document that contains more than a single type of Object is called a Compound Document.

Container Application : An application that contains Linked or Embedded Objects is an container application. Object Embedding: with this technique you can insert an Object from one application into another application. Object Linking: This technique is similar to Object Embedding except that the changes made to the Object Word or Excel in the server are reflected automatically in the container application.

By selecting the Object through insert Object dialog box. Embedding with Drag and Drop : 1. Immediately insert dialog box appears chick on cancel button. Since we are Embedding Object using Drag and Drop. Start an application that supports OLE and open a file. In this exaple, we will start Microsoft Word application and insert a Word Document in the OLE container control by dragging and dropping the document Copy and paste. You can edit it with words Menus and Tool Bars.

Linking and Embedding with insert Object Dialog Box: 1. Immediately insert Object Dialog Box appears. From that Dialog Box select the option create from file option button and check the Check Box. Click on the browse button to locate the file you want to Embed. Immediately the selected file appears on the OLE container control.

ActiveX : What is ActiveX? ActiveX is a reusable and portable software component or control built according to what are called COM Component Object Model specifications. It is the brainchild of Microsoft. It provides a building block solution to complex problems. Visual Basic ActiveX Controls: When you start VB, the first window called the design window shows some 20 intrinsic controls like label, command button, option button etc.

These controls cannot be removed from the Toolbox. These controls can be added to or removed from the Toolbox. You will get the New Project Menu as shown in the figure 1. When you move the mouse pointer over the icon, the names of the controls will appear below them. The Components Dialog Box will appear on the screen as shown in the figure 3.

Select the required control by clicking on the rectangular box at the beginning. After selecting the required controls, click OK. The icons of the selected controls will now appear on the Tool box and you can use them just as you will use any other intrinsic ActiveX control. This is in addition to the intrinsic controls already introduced in earlier versions.

The Common Dialog Control enables the users to create Dialog Boxes open, save, print, setup, font, help and so on in their own applications.

The Animation Control enables the users to play silent avi files producing animation appropriate to the operations performed. The Communication Control describes how to use it with a modem to dial a phone number, interact with another modem or add advanced communication functionality to your applications.

The ListView Control enables the users to organize and view the data in deifferent ways using the View Property. The MAPI Control enables the users to sign-on to an electronic messaging system, access an Inbox, send or receive messages or send file attachments.

The Masked -Edit Control enables the users to create mask platforms that prompt them for date, time currency or customized data input. The MSChart Control enables users to create barchrts, assign and edit backdrops and load data from an array.

The Multimedia Control enables the users to control and manage t5he recording playback of a variety of multimedia using a simple push-button interface. The ProgressBar Control enables the users to get a feedback about a lengthy operation by pictorially displaying a moving coloured bar.

The Slider Control enables the users to select a range of data between a maximum and a minimum setting. The Sysinfo Control enables the users to determine the current operating system, how to monitor and respond to Plug and Play events or changes in AC and battery power status. The Tabbed Dialog Control enables the users to present several dialogs or screens of information on a single form using the same interface.

The TabStrip Control enables the users to create tabs by adding tab objects to the tab collection. Use an imagelist controlo to supply bitmaps for the tabs. This project requires a timer and two labels. The running time will be displayed in one label and the current date will be displayed in the other label. Drag one timer and two label controls into the form. Give the labels appropriate size, font and border and set their caption property blank.

Set the timer interval property as one second and the Enabled property as True. The project at the design time looks as in the below. Entering the Event Codes: Open the code window by double clicking the Timer control and enter the code as shown in the figure 4a.

The clock will begin to run. The current date will be displayed in the other label. The run mode window is as shown in the figure 5. Another important point you notice is that the timer control does not appear in the run mode, and is invisible, but works only from behind.

RichTextBox Control allows the user to enter text with varying fonts and sizes. Set the command button caption and name as font. A font dialog box can be opened only through the Common Dialog control. The Common Dialog control box will be invisible during run time.

Save the form and the project. Enter the codes as shown in the below and finally save the project. ShowFont RichTextBox1. FontName RichTextBox1. FontSize RichTextBox1. FontBold RichTextBox1. FontItalic RichTextBox1. You type any text in the RichTextBox and select it. Click the font button. The font dialog box will open. Set the desired font and size. On deselecting the text, you will find the text printed in the desired font and size.

This includes a set of activities. These activities are 1. Preliminary Investigation 2. Determination of System Requirements 3. Design the System 4. Development of Software 5.

System Testing 6. Implementation and Maintenance. Preliminary Investigation : This activity has 3 parts. Request Classification 2. Feasibility Study 3. So, the project request must be examined to determine what the organizer wants? Feasibility Study: This activity determines whether the study requested is feasible or not. There are 3 aspects in feasibility study i Technical Feasibility : can the project be done with current equipment, available persons and with existing software.

Request Approval: Not all requested projects are feasible and desirable. So, the projects that are feasible and desirable must be put in to schedule. Determination of System of Requirements : Analysis working closely with Employees and Managers must answer these question to determine the system requirements.

What is being done? How is being done? How frequently does it occur? How well the task is being performed? To answer these questions systems analyst take to a verify of persons. Design to the System: The system design describes the data to be input, the data to be output and the procedures. This information is passed to programming staff. So, that software development can begin, Designers are responsible for providing complete and clear information about the system to programmers. Development of Software: For the development of new system software developers install newly purchased software.

System Testing: During system testing the system is used experimentally to test whether the system is according to the requirements. In this activity input is given to the system and the results are examined. Implementation and Maintenance : Implementation is the process of checking the system have to be maintained that is modifications and changes will be made to the software to meet the new requirements.

To draw such data flow diagrams, the different notations used are 1. Process : This represents people procedures or devices that use or procedure data. Source or Destination : This may be people, programs or any other Entities. Data Store : The data store represents data bases each Component in Data Flow Diagram is labeled with a descriptive name. Data Flow Diagrams allows analysts to study how the data enter the process and how they are changed when they leave the process.

If the analyst want to review the overall system hw uses higher level Data Flow Diagrams. If they are instructed in studying one particular process they use lower level Data Flow Diagrams. Using Data Flow Diagrams users can make suggestions for modifications more accurately. These are two types 1. Visual Basic has many built-in functions that are a part of the base language and may be called at any time from your procedures.

Cos ExpN This function returns the cosine of an angle angle in radians Sin ExpN This function Returns the sine of an angle angle in radians String Functions Len str This function returns the number of characters in a string expression Eg.

Eg: Me. Minute Returns an integer between 0 and 59, inclusive, that represents the minute of the hour corresponding to the time provided as an argument Month Returns an integer between 1 and 12, inclusive, that represents the month of the year for a date argument. Practice Application: Program. By clicking the Microsoft Visual Basic 6. Double Click on the Command1 Ok , a Code window will appears. After the completion of a code Save the Project with appropriate name and run the project by pressing the Function Key F5.

The Output is Viewed as shown in figure. Procedure: 1. Output: Program. In the Form Design the Calculator which is shown in the right side by using the related Controls. Double Click the Form , the Code Window will appears.

Text End Sub 9. AddItem "Regular". AddItem "Bold". AddItem "Italic". FontCount List1. AddItem Screen. Fonts i Next End Sub 7. List Combo1. ListIndex Case "Regular" Text1. List List1. ListIndex End Sub 9. After completion of the Code, save the project with an appropriate name and run the project by clicking on the F5 Function Key.

Show End Sub 6. Show End Sub 7. AddItem Text1. Text End Sub RemoveItem List1. RemoveItem Combo1. After Completion of a Code, Save the project with an appropriate name and run the application by pressing F5 Function Key. In the Form design 5 Labels and one rectangle , one combo box, one list box , one Horizontal scroll Bar.

AddItem "Rectangle". AddItem "Square". AddItem "Oval". AddItem "Circle". AddItem "Rounded Rectangle". AddItem "Solid". AddItem "Transparent".

AddItem "Horozontal Line". AddItem "Vertical Line". AddItem "Upward Diagonal". AddItem "Downward Diagonal". AddItem "Cross". This error can be caused by the user, logic or simply the system itself. NET provides various error definitions that we can catch using the Catch with parameters for the unique error we are trapping for.

Or simply trap all errors using the Catch block with no parameters. The statements inside the finally block are executed always. NET error mechanism which stopped execution of the program. Show "Exception was raised" MessageBox. The built-in VB. NET is powerful and offers a variety of features, but can be confusing. NET an exception is really an Object which is either directly or indirectly derived from the Exception Class. What this means is that VB. NET provides a list of Exception classes each specifically design to trap a particular error.

Exception Class, VB. NET provides many standard exception classes for us to use in order to trap for a particular exception. Exception Class contains Properties and methods that we can access with information about the error. Exception Class traps all possible errors.

Exception Class this class traps for all errors. I will not list the other properties. For further info. See VB. NET documentation. Methods of the Exception Class: Method Description GetType This method returns an Object which contains additional information about the type of error.

ToString Similar to the Message Property, but returns the a string containing the error and includes a lot more information about the error, such as path etc. I will not list the other methods. Trapping all Errors using the VB. Exception MessageBox. Both these code trap for all errors. As shown in the next example. NET class for this particular error. Show objException. ToString 'Use exception object's GetType. FullName Method to display name of error type MessageBox.

FullName MessageBox. NET provides many standard exception classes for us to use in order to trap for a specific error.

NET Core, TypeScript along with mastering the skills of building, debugging, and unit testing professional apps, you'll find this book useful. Basic knowledge of Visual Studio,.

NET, and C is assumed. NET is a programmer's complete guide to Visual Basic. Report this file. Account About Us We believe everything in the internet must be free. So this tool was designed for free download documents from the internet. We will then add addi-tional objects and code to create a more complete Visual Basic application. Exercises 2. It is a custom version of the venerable Visual Basic programming language that has powered Microsoft Excel's macros since the mids.

Liew, the webmaster of our popular online Visual Basic Tutorial, vbtutor. This book is a complete guide to mastering Visual Basic , from beginner to intermediate programmers. This book has been written to complement our free online Visual Basic tutorial but with much more content. This ebook is a quick introduction to Visual Basic. NET programming language. It explains the very basics of the language with screenshots showing what is expected to see during development process.

This ebook is the result of combining a number of tutorials available on the site. Output Devices Output is any data the computer sends to the outside world. It might be a sales report, a list of names, a graphic image, or a sound. The data is sent to an output device, which formats and presents it. Get to grips with integrating Visual Studio with Git repositories. Public Domain Mark 1. It covers many different techniques and topics including optimization of programs, object oriented programming and coding guidelines, Windows API, VB6 command reference, and much more.

This practical book offers nearly 50 hands-on projects. For others, that moment comes today, when they use Visual Basic. NET for the first time. This makes development easy! The application was a. See credits at the end of this book whom contributed to the various chapters. In creating this manual we set ourselves the task to develop a minimum program code playing the role of Proxy-server transmitting information from one port to another.

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