Chapter 06
Upcoming SlideShare
Loading in...5
×
 

Chapter 06

on

  • 889 views

 

Statistics

Views

Total Views
889
Views on SlideShare
880
Embed Views
9

Actions

Likes
0
Downloads
17
Comments
0

2 Embeds 9

http://tyoastos.pbworks.com 6
http://www.slideshare.net 3

Accessibility

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment
  • Brief description on how to navigate within this presentation (ppt) The first time a Key Term from the chapter is used in the ppt it will display in blue Gold colored text boxes display coding examples Slides will be numbered (# of #) when multiple slides on same topic (Slide title) Speaker notes are included where appropriate for slides (*)Denotes either a comment for page reference to textbook or slide reference in ppt
  • The new form will display on the screen and be added to the Solution Explorer Window
  • The Solution Explorer window shows the files that are included in a project-you can add new files and remove files from a project
  • About boxes typically hold labels and perhaps an image or shape controls for a logo *The new slide shows an example of a typical About box
  • A typical About box that contains labels, a group box, a picture box, and a button – [suggestion: have students identify each label, group box, picture box and button]
  • A new form created with the About Box template. The form can be customized by setting properties of the controls, adding controls, or removing controls.
  • *The Assembly Information dialog box displays on the next slide
  • Enter or modify the project’s information on the Assembly Information dialog box Once the information is entered into the Assembly Information , it can be retrieved by using the My.Application object.
  • *The next slide displays a custom splash screen created from a standard Windows form
  • The predefined code in the splash screen template may be more complicated than is needed- it includes code to fill in the application title, version, and copyright information from the project’s assembly information
  • Whether you create your own splash screen or use the VB template, you must take one more step to make the splash screen appear before the startup form
  • In code, you can use several methods to show, hide, and close forms
  • Even with a modal form, the user can switch to another application within Windows
  • Form handling in VB .NET 2005 is significantly different than form handling in VB .NET 2003 and earlier versions. VB 2005 automatically creates a form object for each of the form classes that you create. You can show, hide, and close forms without explicitly declaring a new object. This default form object is not actually instantiated until you access one of the form’s objects (such as a text box) or a form method (such as the Show method).
  • It’s helpful to know the order in which the form events occur
  • Double-clicking a control or form opens an event procedure called FormName.Load-there are two easy techniques in addition toe double-clicking
  • Public keyword is not considered a good programming practice Local and block level variables are declared inside a procedure and are always private
  • Using a static local variable is better than using a module level variable because it is always best to keep the scope of a variable as narrow as possible
  • There are general guidelines for helping to decide where to place declarations *Refer to p. 260 for the Declaration Summary for Variables and Constants table

Chapter 06 Chapter 06 Presentation Transcript

  • aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf aslkjdhfalskhjfgalsdkfhalskdhjfglaskdhjflaskdhjfglaksjdhflakshflaksdhjfglaksjhflaksjhf
  • Multiform Projects Chapter 6 McGraw-Hill © 2006 The McGraw-Hill Companies, Inc. All rights reserved.
  • Objectives
    • Include multiple forms in an application
    • Use templates to create splash screens and about boxes
    • Use the Show, ShowDialog, and Hide method s to display and hide forms
    • Understand the various form events and select the best procedure for your code
    • Declare variables with the correct scope and access level for multiform projects
  • Using Multiple Forms
    • Projects can appear more professional when using different windows for different type of information
    • The first form a project displays is a summary form
    • Projects can contain as many forms as desired
  • Creating New Forms
    • Select Add Windows Form from the Project menu and select from many installed templates
  • Switching Between Forms (1 of 2)
    • In design time there are several ways to switch between forms:
      • Solution Explorer window-select a form name and click the View Designer button or the View Code button
      • Double-clicking a form name opens the form in designer
      • Easiest way is to use the tabs at the top of the Document window that appear when the form is displayed
    • Each form is a separate file and a separate class
  • Switching Between Forms (2 of 2) Using Tabs Selecting from drop down list
  • Adding Existing From Files
    • Forms may be used in more than one project-an existing form maybe used in a new project
    • Each form and information for the form is saved as three separate files:
      • Code procedures
      • Visual interface
      • Property settings for the controls
    • To add an existing form to a project use the Add Existing Item command on the Project menu
      • Select only one filename: FormName.vb; all three files are automatically copied into the project folder
  • Removing Forms from a Project
    • Select the file name in the Solution Explorer of the file to be removed
    • Either click the Delete key or right-click on the filename to and choose Delete form the context menu
    • Additional option is to choose Exclude from project to remove the form from the project but not delete the files
  • An About Box (1of 2)
    • One popular type of form in a project is an About box -found in most Windows programs under Help/About
    • Usually provides the name and version of the program and information about the programmer or company
    • Users can create About boxes by creating a new form and entering the information in labels
    • Windows controls can be used on a new form
  • An About Box (2 of 2)
  • Using the About Box Template
    • Visual Studio’s About Box template can be used to create a new About box
    • Choose Add Windows Form from the Project menu and select About Box
  • Setting Assembly Information
    • Users can manually set the Text properties of the controls
    • --OR--
    • Open the Project Designer from Project/ProjectName Properties or double-click the My Project in the Solution Explorer
      • Click the Assembly Information button and fill in the desired information in the Assembly Information dialog box
  • Assembly Information Dialog Box
  • A Splash Screen
    • The initial screen containing a logo or window that is seen while a program is loading
    • Professional applications use splash screens to tell the user that the program is loading or starting
    • Makes a large application appear to load and run faster since something is displaying on the screen while the rest of the application loads
  • Splash Screen Example
  • Using the Splash Screen Template
    • Visual Studio contains splash screen templates
    • Select Project/Add New Item to display the Add new item dialog box and choose Splash Screen
    • Modify the form to fit current needs
    A splash form created using the Splash Screen template
  • Making the Splash Form Display First
    • Display the Project Designer from the Project menu and set the Splash screen drop-down list to the created splash screen
    • Do not change the setting for Startup object or Shutdown mode
    • Then the project is run, the splash screen should display while the startup form is loading and then disappear
    • At times the startup forms loads so quickly that it is nearly impossible to see the splash screen
  • Setting the Splash Screen Example Set the Splash screen drop-down list to the new form in the Project Designer
  • Showing a Form
    • New forms are displayed in response to a user clicking a button or a menu item
    • In the event procedure for the button or menu item use either the Show method or ShowDialog method to display the new form
  • Modal versus Modeless Forms
    • Show method displays a form as modeless -means that both forms are open and the user can navigate from one form to the other
    • ShowDialog method displays a new form as modal -the user must respond to the form in some way, usually by clicking a button
      • No other program code can execute until the user responds to and hides or closes the modal form
    • With a modeless form the user may switch to another form in the project without responding to the form
  • Show Method
    • General Form
    • Example
    • The Show method creates a form object from the specified class and displays it modelessly-the formName is the name of the form to be displayed
    f ormName .Show () summaryForm.Show ()
  • ShowDialog Method
    • General Form
    • Example
    • Use the ShowDialog method when the user is wanted to notice, respond to, and close the form before proceeding with the application-this code is generally placed in a menu item or a button’s click even procedure
    f ormName .ShowDialog () summaryForm.ShowDialog ()
  • Hiding or Closing a Form
    • The Close method behaves differently for a modeless form compared to a modal form
      • Modeless-Close destroys the form instance and removes it from memory
      • Modal-the form is only hidden
    • Choosing a form’s Hide method sets the form’s Visible property to False and keeps the form instance in memory ready to be re-displayed
      • An example would be for form with instructions or Help text
  • Hide Method
    • General Form
    • Example
    formName .Hide() summaryForm .Hide()
  • Responding to Form Events
    • Two primary events that code might be needed for are:
      • FormName.Load-form loaded into memory
      • FormName.Activated-occurs when control is passed to form
    • First time a form is shown in an application the form generates both the Load and Activated events
    • If a form is displayed multiple times, initializing steps can be placed into the Activated event procedure; same for setting the focus in a particular place on a new form
  • The Sequence of Form Events Occurs after the form is closed FomClosed Occurs as the form is about to close FormClosing Occurs when the form is no longer the active form Deactivate Occurs each time any portion of the form is redrawn Paint Occurs each time the form is shown Activate Occurs before the form is displayed for the first time-usually happens only once Load
  • Writing Event Procedures From the Code Editor
    • In the Editor, drop down the Class Name list and choose the entry that shows the events for the selected form
    • In the Method Name list select the event for which to write a procedure—events already having a written procedure appear in bold
  • Writing Event Procedures From the Properties Window in the Designer
    • Select an event using the Properties window
    • Click the form to show properties and click Events button
    • Double-click the event to create an empty event procedure
  • Holding the Splash Screen Display
    • If application are very small the splash screen disappears before it can be read
    • Code can be written to hold the splash screen longer
  • Variables/Constants in Multiform Projects
    • For module-level variables to be available in more than one form in a project it must be declared as Friend or Public and not as Private
    • Scope can be expanded for variable and constants and is the set of statements that can access a variable or constant without qualifying its name
  • Access Level
    • Specifies the permission required to make use of the variable or constant
    • To make a variable available to other forms use either the Public or Friend keywords
      • Friend-allows other forms in the project to access the variable
      • Public-allows all other programs to access variables
    • Private keyword allows access only in the class (form) in which it is declared
    • Only use access level keywords for module level variable
  • Lifetime
    • The period of time that a variable or constant remains in existence
    • Module and namespace variables exist as long as the application runs
  • Static Variables
    • Use to declare local and block level variables
    • Retain their value for the life of the project
    • If the value in a variable needs to be retained for multiple calls to a procedure such as running count, declare it as Static
    • If the variable is used in multiple procedures, declare it at the module level
  • The Static Statement
    • General Form
    • Examples
    Static Identifier As DataType Static personCountInteger As Integer Statis reportTotalDecimal As Decimal
  • Namespaces
    • VB projects are automatically assigned to a namespace
      • Namespaces can be viewed and modified which is called the root namespace
  • Declaring Variables/Constants Guidelines
    • Place all local declarations at the top of a procedure
    • Use named constants for any value that doesn’t change during the program execution
    • Keep the scope of variables and constants narrow
    • Consider making variables local if possible
    • Make variables Static if needed for multiple executions within a procedure
    • If variables are needed for more than one procedure, declare it as local and pass it as an argument
    • Use Private module level variables if using a variable in multiple procedures and displaying in another
    • If using the value of a variable in more than one form declare it as Friend
  • Running a Program Outside the IDE
    • The .exe file can be moved to another computer, placed on the system desktop, or used as a shortcut just like any other application
    • If copying the .exe file to another system make sure it has the Microsoft.NET Framework
      • Can download the framework for free from the Microsoft
      • Web site
    • Change the icon if desired