Vb .net Tutorial - 2

Creating Windows Forms Objectives In this lesson, you will learn to: ☛Identify the features of Windows Forms ☛Identify various language features required to work with Windows Forms ☛Identify various Windows Forms controls ☛Create Windows Forms

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Creating Windows Forms Understanding the User Interface ☛ A user interface is the means by which a user interacts with an application. A well-designed user interface is an effective means of making an application user-friendly. ☛ Types of User Interfaces ✓ Character user interface (CUI) ✓ Graphical user interface (GUI)

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Creating Windows Forms Windows Form ☛ Is a representation of any window displayed in an application. ☛ Is used to accept input from a user and display information.

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Creating Windows Forms Windows Forms (Contd.) ☛Windows Form properties: ✓ Are used to determine the appearance of a Windows Form at run time. ✓ Some commonly used properties are: ➤Name ➤BackColor ➤BackgroundImage ➤Font ➤Size ➤StartPosition ➤Text ➤WindowState ©NIIT

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Creating Windows Forms Windows Forms (Contd.) ☛Windows Forms events: ✓ Click ✓ Closed ✓ Deactivate ✓ Load ✓ MouseMove ✓ MouseDown ✓ MouseUp

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Creating Windows Forms Windows Forms (Contd.) ☛Windows Forms methods: ✓ Show() ✓ Activate() ✓ Close() ✓ SetDesktopLocation()

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Creating Windows Forms Visual Basic.NET Language Features ☛Data types: ✓ Byte ✓ Short ✓ Integer ✓ Long ✓ Single ✓ Double ✓ Decimal ✓ Boolean ©NIIT

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Creating Windows Forms Visual Basic.NET Language Features (Contd.) ☛Data types: (Contd.) ✓ Char ✓ String ✓ Date ✓ Object

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Creating Windows Forms Visual Basic .NET Language Features (Contd.) ☛Variables ✓ Allow you to store data. ✓ Have a data type and a name. ✓ Can be declared by using the Dim statement. ☛Arrays ✓ Are collections of values of the same data type. ✓ Contain elements that can be accessed using a single name and an index number representing the position of the element within the array.

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Creating Windows Forms Visual Basic .NET Language Features (Contd.) ✓ Are declared using the following syntax: Dim arrayname(Number-of-elements) as datatype ✓ Can be resized using the Redim statement. ☛Operators ✓ Are used to process the data entered by a user. ✓ Can be categorized as follows: ➤Arithmetic operators such as +, -, *, /, \, and Mod ➤Comparison operators such as =, <, >, <=, >=, and <> ➤Logical operators such as And, Or, Not, and Xor ➤Concatenation operators such as & and + ©NIIT

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Creating Windows Forms Visual Basic .NET Language Features (Contd.) ☛Control flow constructs ✓ Decision structures ➤If-then-else ➤Select case ✓ Loop structures ➤While-End while ➤Do-Loop ➤For-Next ✓ Nested control statements ©NIIT

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Creating Windows Forms Just a Minute… 1. Write a loop structure to display all odd numbers between 1 and 100. 2. Write the construct to check whether the character stored in the variable X is a vowel and display an appropriate message.

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Creating Windows Forms Problem Statement 2.D.1 For the Call Center application, a startup screen needs to be provided to accept the user name and password. The application should allow the user to enter the user name and password for a maximum of three times. If in all of the three attempts, a wrong user name and password is entered, the application should display an error and close.

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Creating Windows Forms Task List ☛ Identify the variables required to store the values in the application. ☛ Identify the controls to be used for accepting input from the user. ☛ Identify the mechanism to validate the user input. ☛ Create a Windows Form. ☛ Add controls to the Windows Form. ☛ Write the code to validate the user input. ☛ Execute the application.

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Creating Windows Forms Task 1: Identify the variables required to store the values in the application. Result: ☛The variables required for accepting the login details from a user are: ✓ Counter ✓ Login Name ✓ Password

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Creating Windows Forms Task 2: Identify the controls to be used for accepting input from the user. ☛Visual Basic .NET provides a number of controls that can be added to a form: ✓ TextBox ➤Is used to display text to a user or accept input from a user. ➤Has the following properties: ➤ Text ➤ Multiline ➤ Passwordchar

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Creating Windows Forms Task 2: Identify the controls to be used for accepting input from the user. (Contd.) ✓ Label ➤Is used to provide information or description of another control on the Windows Form. ➤Has the following properties: ➤ Text ➤ AutoSize

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Creating Windows Forms Task 2: Identify the controls to be used for accepting input from the user. (Contd.) ✓ LinkLabel ➤Is used to display the text as a link. ➤Has the following properties: ➤ LinkColor ➤ ActiveLinkColor ➤ DisabledLinkColor ➤ LinkVisited

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Creating Windows Forms Task 2: Identify the controls to be used for accepting input from the user. (Contd.) ✓ ListBox ➤Is used to display a list of items to a user. ➤Can be populated by using the Add() method of the Items collection. ➤Has the following properties: ➤ SelectionMode ➤ Sorted

➤ SelectedIndex ➤ SelectedItem ©NIIT

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Creating Windows Forms Task 2: Identify the controls to be used for accepting input from the user. (Contd.) ✓ ComboBox ➤Is used to display a drop-down list of items. ➤Can be populated by using the Add() method of the Items collection. ➤Has the following properties: ➤ Text ➤ Sorted ➤ SelectedIndex ➤ SelectedItem

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Creating Windows Forms Task 2: Identify the controls to be used for accepting input from the user. (Contd.) ✓ CheckBox ➤Is used to set Yes/No or True/false options. ➤Has the following properties: ➤ Text ➤ Checked

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Creating Windows Forms Task 2: Identify the controls to be used for accepting input from the user. (Contd.) ✓ RadioButton ➤Is used to provide a set of mutually exclusive options to the user. ➤Has the following properties: ➤ Text ➤ Checked

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Creating Windows Forms Task 2: Identify the controls to be used for accepting input from the user. (Contd.) ✓ GroupBox ➤Is used to group related controls. ✓ Button ➤Is used to perform an action when a user clicks it. ➤Has the Text property, which is used to set the text displayed on the button. ✓ StatusBar ➤Is used to display the status information. ➤Has the following properties: ➤ ShowPanels ➤ Text ©NIIT

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Creating Windows Forms Task 2: Identify the controls to be used for accepting input from the user. (Contd.) ☛Some common properties found in most of the controls are: ✓ Name ✓ Visible ✓ Location ✓ Enabled

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Creating Windows Forms Task 2: Identify the controls to be used for accepting input from the user. (Contd.) ☛Some common events found in most of the controls are: ✓ KeyDown ✓ KeyUp ✓ KeyPress ✓ MouseDown ✓ MouseUp ✓ MouseMove ✓ ReSize ✓ VisibleChanged

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Creating Windows Forms Task 2: Identify the controls to be used for accepting input from the user. (Contd.) Result: ☛You will use the following controls for the given problem statement: ✓ Label ✓ TextBox ✓ Button

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Creating Windows Forms Task 3: Identify the mechanism to validate the user input. Result: ☛The program should use the If-Then construct to validate the user name and the password. The If‑Then construct can also be used to ensure that value of the counter is not greater than 3.

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Creating Windows Forms Task 4: Create a Windows Form. Task 5: Add controls to the Windows Form. Task 6: Write the code to validate the user input. Task 7: Execute the application.

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Creating Windows Forms Just a Minute… You have created two forms named Form1 and Form2. Write the code so that when a user clicks the OK button in Form1, Form2 should be displayed.

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Creating Windows Forms Problem Statement 2.P.1 Diaz Telecommunications needs an application to accept order details. The details to be accepted include order number, date, customer ID, product ID, cost, and advance. The product IDs should be displayed in a combo box. When a user clicks the Save button after entering order details, the application should verify that none of the fields is left blank and display an appropriate message.

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Creating Windows Forms Summary In this lesson, you learned that: ☛A form is used to accept input from the user and present information to the user. ☛An event gets generated on performing an action such as clicking the mouse or pressing a key from the keyboard. ☛When an event is raised, the code within the event handler is executed. ☛Variables are used to store data at run time. You can declare a variable by using the Dim statement. ☛The decision structures supported by Visual Basic .NET include: ✓  If-Then-Else

✓ Select-Case ©NIIT

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Creating Windows Forms Summary (Contd.) ☛ The loop structures supported by Visual Basic .NET are: ✓ While-End While ✓ Do-Loop ✓ For-Next ☛ Controls can be added to a form to accept input from the user or display some information on the form. ☛ Some commonly used controls are TextBox, Label, CheckBox, RadioButton, and Button.

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