Windows Form Applications 101

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Windows Form Applications 101

• Creating Windows Form Applications
• The Basics
• Stephany Coffman-Wolph
• 2/9/09

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GUI

• GUI Graphical User Interface
• Allows the user to interact visually with a
  program
• This is the make it pretty part

3
Building GUI

• GUI's are built from GUI controls
• Also known as components or widgets (i.e., window
  gadgets)
• Objects that can display information on the
  screen or enable users to interact with an
  application via the mouse, keyboard or other form
  of input
• Basic Examples
• Label, TextBox, Button, CheckBox ComboBox, ListBox

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Windows Forms

• Used to create the GUI's for programs
• Is a graphical element that appears on the
  desktop (dialog, window, etc)

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Component

• Is an instance of a class that implements the
  IComponent interface
• Remember interfaces from the polymorphism
  material they define what operations can happen
  but not how they are performed
• Controls are components
• Some have graphical representation (i.e., Form,
  Button, Label)
• Others do not (i.e., Timer)

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Commonly Used Types of Controls

• Buttons
• Textboxes
• Labels
• ListBox
• CheckBox

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Toolbox

• The Controls and Components of C are found in
  the C Toolbox
• They are organized by functionality
• To add a component to a Form, select that
  component from the toolbox and drag it onto the
  Form

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Using the Toolbox

• The toolbox is located on the left-hand side of
  the Visual Studio screen
• Click on the control you want to add and drag it
  to the form

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Control Properties and Methods

• Each control has properties (and some methods)
• Some example properties
• Enable
• Font
• Text
• Visible
• Some example methods
• Hide
• Select
• Show

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Editing the Properties

• Click on the control you want to change the
  properties of (i.e., the name, what is displayed,
  etc)
• You can make these changes in the properties
  window located on the bottom right

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Naming Controls

• By default in C, controls/components names are
  button1, label1, textbox1, etc.
• However, these names are not very descriptive
• So like variables, we want the names to have
  meanings that make sense
• There are lots of ways to handle naming of the
  controls/components

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Start the control name with...

• Control
• Button
• TextBox
• ListBox
• Label
• SaveFileDialog

• Begin name with
• btn
• txt
• lbox
• lbl
• sfd

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Control Name Examples

• If the button is used to calculate a total, then
  a possible name for the button would be
• btnCalcTotal
• If the textbox allows the user to enter their
  name then a possible name for the textbox might
  be
• txtEnteredName

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Event Handling

• When a user interacts with a form this causes an
  event to occur (i.e., click a button, type in a
  textbox, etc)
• These events signal that certain code should run
  and perform some sort of action
• All GUI controls have associated events
• Event Handler method that runs after an event
  occurs
• Event Handling the overall process of
  responding to events

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Clicking a Button Event Handler

• The following code is for a button named btnQuit
• When the button is clicked, the form closes
• private void btnQuit_Click(object sender,
  EventArgs e)
• this.Close()

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How to write code for an event...

• Once the control is on the form and you have
  edited the properties, double click the control
• You were is design view
• This will show you the code for the form
• You are now in code view

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Fun with Textboxes

• A textbox is an area in which text can be
  displayed or users can type in text
• A password textbox is a textbox that hides the
  information entered by the user
• Are these different controls?
• No! A textbox is simply a textbox
• Password textbox is a normal textbox but with the
  property UseSystemPasswordChar set to true
• (false is the default setting)

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Example Log-in Screen

• Drag Two Label controls onto the form
• Use the properties to change the default names
• Drag Two Textbox controls onto the form

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Making the Textbox for Password

• Click on the second of the two textboxes
• Find the UseSystemPasswordChar Property in the
  Properties and change to true

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How to Get Info Out of Textbox

• OK, so lets say your textbox is named txtUserName
• To get information a user typed into a textbox
  you use the following
• string userName txtUserName.Text
• Display information into the textbox you use
• txtUserName.Text my string...
• Make the textbox be empty
• txtUserName.Text

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Multiple Forms?

• Can you have multiple forms?
• Yes!
• How is this accomplished?
• By passing the form reference during a call to
  the constructor...
• Similar to passing variables or objects when
  dealing with classes, etc

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Let's Begin with a simple Form1
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Code for FormLogin