Component Tray
Menu and contextmenu
Splash Screen

• Mainmenu
• Context menu
• Errorprovider
• Splashscreen
• Cellular automata

• Timer
• Errorhandlers
• Print capabilities
• DialogBoxes
• Menus
• Context menus

• Most apps nowadays have menus – MS powerpoint and the VB IDE both do.

Add Mainmenu to component tray from toolbox

Selecting the mainmenu control allows you to begin editing the menu

and editing…and editing

add submenus to a menu item by filling in the little box that appears below or next to it.

As with other controls, it is a good idea to rename menu items from MenuItem1,…to mnuFile, …

• You can add shortcut keys to a menu item by selecting shortcut in the properties for this item. Select the shortcut you wish to associate with the menu item.

• Menu items display their submenus automatically if they have them.
• You add itemclick subs to add functionality to menu items that have no submenu.

•
• Private Sub mnufilesave_Click(ByVal sender As
System.Object, ByVal e As System.EventArgs)
Handles mnufilesave.Click
MessageBox.Show("save selected",
"Menu", MessageBoxButtons.OK,
MessageBoxIcon.Asterisk)
• End Sub

• A context menu is added (to the form component tray) from the toolbox.
• When you right-click a control information can be displayed.

Add context menu to a control in properties

Add to context menu as you would to a regular menu

Private Sub ContextMenu1_Popup(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles
ContextMenu1.Popup
MessageBox.Show("context", "context",
MessageBoxButtons.OK,
MessageBoxIcon.Asterisk)
End Sub

• In p:\vs\menu

• Handling errors with an errorprovider
• It is added to the component tray

• An errorprovider is added to the component tray
• In this project the “causes validation” property of the two textboxes are both set to true
• Just the validation code was written – no other processing

Build error provider when form is loaded
Private Sub frmmain_Load(ByVal sender As
System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
errorhandler = New ErrorProvider()
End Sub

Corrected one error, now have another

Two event handlers provided – the validation for the textboxes
Private Sub txtint_Validating(ByVal sender As System.Object, ByVal e
As System.ComponentModel.CancelEventArgs) Handles txtint.Validating
Dim int As Integer errorhandler.SetError(txtint, "")’ clear any old errors
Try int = Integer.Parse(txtint.Text)
Catch ex As Exception errorhandler.SetError(txtint, "field must be int") e.Cancel = True ‘cancel event
End Try
End Sub

Private Sub txtss_Validating(ByVal sender As System.Object, ByVal e As
System.ComponentModel.CancelEventArgs) Handles txtss.Validating
' Me.Refresh() errorhandler.SetError(txtss, "")
Dim ss As String ss = txtss.Text
If ss = "" Then errorhandler.SetError(txtss, "field required") e.Cancel = True
ElseIf ss.Length <> 11 Then e.Cancel = True errorhandler.SetError(txtss, "field must contain 11 chars")
ElseIf ss.Substring(3, 1) <> "-" Or ss.Substring(6, 1) <> "-" Then
‘’’’’there’s more
End If
End sub

• In p:\vsp\errorprovider\bin\...
• There is more to do with this example… like enable navigation and exit without correcting the error.

Splash screen: comes up briefly with some info when a form is loaded

• Create a main form with just a label and exit button
• Add the exit code
(me.close())
• Add a second form to the project called frmSplash

• On frmsplash put:
• Information about the application, copyright, programmer, date, pictures, whatever.

• Add a timer with interval 5000 to the frmspash. In the timertick sub put
– Me.Close() ‘close form after 5 sec
• Be sure to start the timer in the frmsplash load sub.

Splash screens: set topmost property to true

set frmsplash formborderstyle to fixedtool
(so it can’t be resized)

• Add formload code to create an instance of the frmsplash. Recall this code is:
Dim x as frmsplash x.show()
• When frmsplash loads it will start its timer.
• Exe in p:\vs\splash\splash.exe

Cellular automata: in p drive vb folder

• There are many examples of uses of cellular automata, from biological modeling to designing fabric patterns.
• I cover only a little bit about them here.
• Discussion of 2-d automata
• Discussion of 1-d automata

One dimensional automata
• The original values are stored in an array. These might be generated randomly, or come from measurements.
• Display (in VB) might be in a panel.
• The “first generation” consists of a single set of rectangular colors. Each color represents an integer in the array.
• The next generation is computed from the first (usually) according to some formula for example:
• Newvalue(i)=(old(i-1)+old(i)+old(i+1)) mod maxcolors
• You’ll need two one dimensional arrays, and you’ll have to keep copying the new values back into the old array, and displaying .

Two dimensional automata
• Two d automata are displayed similarly to one-dimensional ones: each value represents a color.
• But each new generation is computed in two dimensions, often using some rule about how many neighbors a given cell has in the current generation.

Two dimensional automata
• A sketch of the code goes like this:
1. Assign initial values to a fairly large (like
100X100) array.
2. Loop a bunch of times or do on buttonclick:
3. Compute next generation values into a new array
4. Display the current generation
5. Copy next generation into current
6. endloop

Example..in p:\vb\twodcellularautomata.exe