VB.Net Basics

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VB.Net Basics

• R. Johnson ITE 285

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Designing a GUI

• Form the on screen window your program owns
• TOE Chart Task, Object, Event
• Task your interface helps user perform
• Object the VB control you will use
• Fired Event for which you will write code to
  respond. May be N/A.
• Also dont forget a simple sketch!!!

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TOE Chart
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Command Button

• Task major user-initiated action
• Common Properties
• Name (the variable name)
• Text (what is displayed)
• Prefix btn
• Click event procedure where you put code.

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Textbox

• Task enter/edit text
• Common Properties
• Name, Text
• TextAlign, Readonly
• CharacterCasing
• Multiline
• Prefix txt

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Label

• Task static cosmetic text, describe a textbox,
  or sometimes display output
• Common Properties
• Name, Text
• UseMnemonic
• Prefix lblnon-default name only needed if you
  use at runtime

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Checkbox

• Task make a simple yes/no setting
• Common Properties
• Name, Text
• Checked (a boolean)
• Prefix chk

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Radiobutton

• Task Exclusively pick one option from a group of
  possible settings.
• Common Properties
• Name, Text
• Checked
• Prefix rad
• Usually with Groupbox

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Groupbox

• Purpose
• Visually group related controls for clarity
• Define a set of radiobuttons
• Common Properties
• Prefix

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More on Properties

• We will be using many other properties of these
  controls!!

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Not in the Toolbox

• Inputbox
• Messagebox
• Similar to JOptionPane dialogs in Java
• Only use on exceptional basis!!!!!

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Keyboard Issues

• Focus
• Currently highlighted control will receive
  keystrokes, has the focus.
• Focus is advanced to next control by mouse click
  on it or pressing the Tab key.
• Tab Order
• Default order is order in which created.
• Edit order interactively ViewgtTab Order
• Or TabIndex property of each control.
• Access Keys
• in Text value works with Alt- as a keyboard
  shortcut

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VB.Net IDE

• IDE Integrated Development Environment
• Contains source code editor, compiler, debugger,
  help.
• Similar in concept to JGrasp or Eclipse.

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New Project Dialog

• Make sure you set the location where you want
  it!
• Name is used for new folder as well as files.

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Project Workspace w/Form
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Toolbox

• Double-click or dragndrop to place control on
  Form
• Click in toolbar if hidden
• Your controls are objects, instances of the
  control class.

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Properties

• If hidden
• AZ button sorts alphabetically
• Click in value field for button to see predefined
  list

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Writing Code

• When using the Design view to add controls and
  adjust Properties, code is written for you.
• Add your code in Code View
• Dbl-click on a control in Design View to open
  Code View for its default Event Handling
  Procedure
• Can switch views with tabs at top
• Most of our code for now will be in Event
  procedures

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Compiling and Running

• Build menu compiles and links
• Debug menu has Start to run, or Play button in
  toolbar.

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Build (Syntax) Errors

• ALWAYS click No on a build error!
• Task List at bottom left will show error msg.
  
• Dbl-click msg to highlight suspected line of code
  in source window.

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Solution Explorer

• Rename your form from the default Form1 to
  something like frmMain (in Properties).
• Next, rename the file the same, eg frmMain.vb
• Set the projects Startup Object to the new name
  (menu ProjectgtProperties)

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Project FilesDefault location is underMy
DocumentsgtVisual Studio ProjectsgtYourProjectName
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Project Files 2

• You can load project by dbl-clicking Project
  (.vbproj) or Solution (.sln) file.
• The compiled executable (.EXE) is in the bin
  folder.
• NEVER save files to a floppy using FilegtSaveAs
  from inside Visual Studio!
• Always save everything, exit VS, then copy entire
  project folder.