Visual Basic is a widely used tool for developing Windows applications using a graphical user interface (GUI). An application contains objects like controls and forms that have properties and methods. Common controls include buttons, textboxes, and listboxes that allow user input and display output. Events trigger event procedures to handle user interactions.

1. Windows GUI
Controls and Events
VB.NET
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2. Windows GUI
Visual Basic is the most widely used tool
for developing Windows applications.
Windows applications utilise a GUI that
provides visual cues to the user that allow
the user to work intuitively and efficiently.
Windows applications contain WYSIWYG
“What You See Is What You Get”
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3. Working with Objects
An object is anything we might use in our
application for acquiring, manipulating, or
presenting data or information.
An object contains properties (data) and
methods (actions for manipulating an
object’s data).
An object is defined once as a class.
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4. Working with Objects (cont.)
The developer creates as many instances of the
object as necessary for the application.
The .NET class library is a large library of
classes with reusable code included in the
Microsoft .NET Framework.
.NET uses namespaces, which are collections of
related classes/
 System.Windows.Form is the namespace containing
classes for creating Window based applications.
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5. Reuse and Reliability
One of the most powerful features of object
classes is that they are reusable.
The Control class contains numerous
properties and methods common to all
controls for developing the user interface.
Objects can enhance reliability, which is
the result of good design and lots of
testing.
 Do not reinvent the wheel
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6. Control Objects
The Button control is considered to be the
most basic graphical control.
The Label control is used to display text
that cannot be edited by the user.
The PictureBox control is used to display
graphics.
The Timer control is used to raise an event
at user-defined intervals.
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7. Controls
Menus
Pictureboxes
Labels
Timers
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8. Controls
Understand and effectively use the TextBox,
ListBox, and ComboBox controls
A TextBox control provides GUI form input by
providing an area on the form where the user can
enter data while the program is executing.
A ListBox control provides GUI form input as a
list of items that the user can select by clicking.
A ComboBox control combines the functionality
of the TextBox and ListBox controls.
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9. TextBox Control
The TextBox control provides an area for
the user to enter data while the program is
executing.
TextBox controls can also be used to
display output on the form.
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10. TextBox Properties
Property Description
Name (“txt” prefix) used to access the control in code
Font Gets or sets the font of the text displayed in the control
Maxlength Sets the maximum number of characters allowed
Multiline Allows more than a single line of text to be entered
Passwordchar Sets the character used to mask typed text (Single line only)
ReadOnly Stops text from being edited by the user
ScrollBars Sets which ScrollBars appear (Multiline only)
Text Gets or sets the text displayed in the control
WordWrap Indicates if text is automatically wrapped to next line
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11. TextBox Methods
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12. ListBox Control
The ListBox control makes a visible list of
items.
The user can select items in the list using
mouse clicks.
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13. ListBox Properties
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14. ListBox Methods
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15. ComboBox Control
The ComboBox control combines the
functionality of the TextBox and ListBox
controls.
The user can select values from the drop-
down list or enter values directly into the
text box area.
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16. ComboBox Properties
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17. Working with Events
Visual Basic supports event-driven
programming in which the application
recognizes and responds to events.
An event is an action or occurrence
recognized by some object and for which
you can write code to respond.
And event handler contains code that
responds to a particular event.
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18. Event Procedures
The naming convention for an event
procedure is the keyword Sub followed by
the name of the triggering object followed
by an underscore character followed by the
name of the event e.g. Timer event
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19. Summary
Visual Basic is an object-oriented, event-driven
language.
An object is a self-contained entity that has both
properties and methods.
Most of the objects you will need are available in
VB. NET (forms & controls are objects)
An event refers to an action or change detected by
a program.
An event procedure is the method that handles or
responds to an event.
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