CHAPTER TWO Creating Simple Visual Basic.NET Windows Applications

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 2- 2 Chapter Introduction The Integrated Development Environment (IDE) is used for modern software development. The IDE contains tools to write code, build a GUI, and test and debug applications. Overview of the application construction process. Design issues are addressed. Visual Basic.NET controls are examined. The MsgBox statement and InputBox() function are visited. A project is developed as a working application.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin From New Solution to Finished Application Overview of the Construction Process –Visual Basic.NET runs under Windows. –The programmer creates the application. –The project is an application under construction. –The application is saved to disk periodically. –An executable file is generated from the finished application program.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 2- 4 Visual Basic.NET’s Three Modes Design Mode –Placing, arranging, and customizing the appearance of buttons, labels, and other controls on a form. –Writing processing scripts (source code). –Saving the solution. –Making an executable file.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 2- 5 Visual Basic.NET’s Three Modes (cont.) Run Mode –Executes the solution. –Used to evaluate the workability of a part of the project. –Used to show the user how the solution will work.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 2- 6 Visual Basic.NET’s Three Modes (cont.) Break Mode –Helps the developer with debugging. –Enables the developer to switch back to run mode or design mode.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 2- 7 Design Time and Run Time In design mode, the project is in design time. In run mode, the project is in run time. Some errors can be found and corrected in design time. Other errors can only be detected during run time.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Overview of Controls Standard controls are used to create user- friendly applications. Standard controls help users lower the learning curve for new programs.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 2- 9

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Categories of Controls Trigger: Initiate processing –Ex. Button, MainMenu, and Timer Input: Get data from user –Ex. TextBox, RadioButton, and CheckBox Output: Display results to user –Ex. Label, DataGrid, and ListView

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Categories of Controls (cont.) Organize: Group other controls –Ex. Form, GroupBox, and Panel Data Access: Interface with databases –Ex. Entire Data Group and DataGrid

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin The Correct Control for the Job Chose controls to satisfy user requirements. Different controls are good for different tasks. The Button, Label, and Textbox controls are introduced.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin The Visual Basic.NET Development Environment The IDE helps develops create efficient and effective solutions. The IDE for Visual Basic.NET is common to all the other tools available in the Visual Studio. NET suite.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Getting Started Open an existing project or begin a new project from the Start Page. Use the My Profile option to set up the IDE.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Visual Basic.NET Solution Structure Every application will be organized as a “solution.” Solution Explorer is an interface for viewing and managing containers and associated items. Items are files that make up your project, such as forms, source files, and classes.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Main Tools Used in Visual Basic.NET Menu Toolbar Solution Explorer Properties Editor Task List Toolbox Designer Window Code Window Help System (Ctrl-F1 for Dynamic Help)

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Saving a Solution Save your solution and all its contents on a regular basis. Each project should be in its own separate folder. Avoid the temptation to use the Save As…, save option. Use the Save and Save All Toolbar icons.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 2- 18

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Introducing the Windows Form Control The window that is displayed when the application is running. The IDE automatically creates a Windows Form when you start a new project. This form will hold or “contain” other controls.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin The Button Control React to the click of the use Perform a task associated with the name of the button that is displayed on its face.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Appearance and Use Appears as a rectangular-shaped control on a form. Its face can display text, an image, or both. The face of the button should clearly indicate its function.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Properties The most common properties of the Button control are listed. Most properties are available for every control.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Common Properties of the Button Control Name BackColor BackgroundImage Enabled Font ForeColor Image ImageAlign TabIndex TabStop Text TextAlign Visible

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Events Components are able to respond to events. The click event is generated when the user clicks the mouse button. You write code to handle events. Double-click the Button control to automatically open the code window.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin The Label Control Used to display information to the user. Used to label other controls or show results of a calculation. –Ex. Check box and radio button labels.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Appearance and Use Appears as a rectangular area that can be filled with text. You have some control over size and alignment of text. You can include a border around the label.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Properties Many of the Button control properties apply to the Label control. The Text Property is the most-used property for the Label control.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Common Properties of the Label Control Name AutoSize BorderStyle DataBindings Font ForeColor Image ImageAlign Text TextAlign

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Events Example 2.1 Using the Label Control –Demonstrates two main uses of the Label control To display a message to the user. To display “labeling” information for the user.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin The TextBox Control Provides an area for the user to type while the program runs.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Appearance and Use Displays as a rectangular area that provides the user a place to type. You can limit the user types You can also surround the TextBox with a border.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Properties Some of the TextBox control properties are only available at run time. The value of the Text property is used most frequently. Control of user entry is shared between properties and events. The PasswordChar property allows you to set a security character.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Properties (cont.) TextLength property determines the number of characters contained in a textbox. Selection… properties provide information on user selections in the TextBox control.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Common Properties of the TextBox Control Name AcceptsReturn AcceptsTab AutoSize BorderStyle CharacterCasing Font Lines MaxLength Modified Multiline PasswordChar ReadOnly ScrollBars SelectedText SelectionLength SelectionStart Text TextAlign TextLength WordWrap

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Events Focus means the user is currently working with the specific control. Enter - Occurs when input focus is received. KeyPress - Occurs when a key is pressed while the control has focus. Leave – Occurs when input focus leaves the control.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Events (cont.) Methods –Enable the developer to manipulate text in a TextBox. –Many are available to the developer.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Common Events for the TextBox Control Enter KeyPress Leave AppendText Clear Copy Cut Paste Select SelectAll Undo

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin The MsgBox Statement and InputBox Function Two alternate ways to receive information from the user and to display information on the screen.

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin MsgBox Statement The MsgBox statement will display information that requires user intervention. –MsgBox(“A prompt”, Buttons,”A title”)

©2002 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin InputBox() Function The InputBox() function requests information from the user with a dialog box. It requires user intervention. –InputBox(“A prompt”,”A title”,”A default response”)