Browse All Articles > Implementing control arrays in VB.net
PROBLEM
The project I am currently working on is MMPI test module. One of the most challenging parts was to develop a user interface that will accommodate answers for over 560 questions with three options (True, False, Don't care / pass) each. This would have been done this in VB6 using three control arrays of radio buttons. But in VB.Net, control arrays are no longer supported.
SOLUTION
Then I found out that VB.Net supports classes. I was fascinated as always with concept of OOPS, and applied it to my need. The result was fabulous. Here is the code for the class and a function which uses the code from a VB.Net form. Without the class I would have ended up drawing manually 600*3=1800 radio buttons on the form and then linking them with appropriate check changed event, which would have been a nightmare for a lazy fellow like me.
You can vary this code in any form to accommodate controls other than radiobuttons.
Code explanation:
The Code for this array is very simple.
1. I made a Groupbox control using code inside the class Questionarraysa and attached four controls to the groupbox(3 radio buttons and a label). No need to load the controls just use Add function of Controls collection of Groupbox to attach controls
2. After which I Positioned each of the controls within the Groupbox by setting their Top and Left properties.
3. Finaly I attached the Checkchanged Event to each of the radiobuttons, to the functions I wrote. Now one question template class is ready. The calls function AddNewQuestion will return a Groupbox control (which will contain the label and radiobutton controls in it).
4. In the form then, an array of the template class (Questionarray) was declared and for each element Addnewquestion was called.
5. The groupbox which was returned by the call was then attached to the form using Add function of the Controls collection.
The effect is the array shares code for the Eventhandler and we can identify each element uniquely using Array index as in VB 6.0
The project I am currently working on is MMPI test module. One of the most challenging parts was to develop a user interface that will accommodate answers for over 560 questions with three options (True, False, Don't care / pass) each. This would have been done this in VB6 using three control arrays of radio buttons. But in VB.Net, control arrays are no longer supported.
SOLUTION
Then I found out that VB.Net supports classes. I was fascinated as always with concept of OOPS, and applied it to my need. The result was fabulous. Here is the code for the class and a function which uses the code from a VB.Net form. Without the class I would have ended up drawing manually 600*3=1800 radio buttons on the form and then linking them with appropriate check changed event, which would have been a nightmare for a lazy fellow like me.
You can vary this code in any form to accommodate controls other than radiobuttons.
Code explanation:
The Code for this array is very simple.
1. I made a Groupbox control using code inside the class Questionarraysa and attached four controls to the groupbox(3 radio buttons and a label). No need to load the controls just use Add function of Controls collection of Groupbox to attach controls
2. After which I Positioned each of the controls within the Groupbox by setting their Top and Left properties.
3. Finaly I attached the Checkchanged Event to each of the radiobuttons, to the functions I wrote. Now one question template class is ready. The calls function AddNewQuestion will return a Groupbox control (which will contain the label and radiobutton controls in it).
4. In the form then, an array of the template class (Questionarray) was declared and for each element Addnewquestion was called.
5. The groupbox which was returned by the call was then attached to the form using Add function of the Controls collection.
The effect is the array shares code for the Eventhandler and we can identify each element uniquely using Array index as in VB 6.0
Public Class QuestionsArray
Inherits System.Collections.CollectionBase
Private mywindow As System.Windows.Forms.Form
Public TrueButton As System.Windows.Forms.RadioButton
Public FalseButton As System.Windows.Forms.RadioButton
Public DButton As System.Windows.Forms.RadioButton
Public AnswerGroup As System.Windows.Forms.GroupBox
Public QstNo As System.Windows.Forms.Label
Private Questionno As Integer
Private Answer As String
Sub New(ByVal Questionno1 As Integer, ByVal QSTWIND As System.Windows.Forms.Form)
Questionno = Questionno1
mywindow = QSTWIND
TrueButton = New System.Windows.Forms.RadioButton
FalseButton = New System.Windows.Forms.RadioButton
DButton = New System.Windows.Forms.RadioButton
AnswerGroup = New System.Windows.Forms.GroupBox
QstNo = New System.Windows.Forms.Label
End Sub
Public Function AddNewQuestion(ByVal Questionno As Integer, ByVal toppos As Integer, ByVal leftpos As Integer) As System.Windows.Forms.GroupBox
Dim a As EventArgs
Dim leftst = 10
AnswerGroup.Controls.Add(QstNo)
AnswerGroup.Controls.Add(TrueButton)
AnswerGroup.Controls.Add(FalseButton)
AnswerGroup.Controls.Add(DButton)
Dim ctlwidth As Integer
Dim ctlspacing As Integer
ctlwidth = 50
ctlspacing = 60
QstNo.Top = 15
QstNo.Left = leftst
QstNo.Width = 0.6 * ctlwidth
QstNo.Text = Questionno.ToString() & "."
TrueButton.Top = 10
leftst = leftst 0.6 * ctlspacing
TrueButton.Left = leftst
TrueButton.Width = ctlwidth
TrueButton.Height = 24
TrueButton.Text = "True"
AddHandler TrueButton.CheckedChanged, AddressOf AnswerkeysT
FalseButton.Top = 10
leftst = leftst ctlspacing
FalseButton.Left = leftst
FalseButton.Width = ctlwidth
FalseButton.Height = 24
FalseButton.Text = "False"
AddHandler FalseButton.CheckedChanged, AddressOf AnswerkeysF
DButton.Top = 10
leftst = leftst ctlspacing
DButton.Left = leftst
DButton.Width = 2.5 * ctlwidth
DButton.Height = 24
DButton.Text = "Don't care/Pass"
leftst = leftst 2.7 * ctlwidth
AddHandler DButton.CheckedChanged, AddressOf AnswerkeysD
AnswerGroup.Width = leftst
AnswerGroup.Height = 40
AddNewQuestion = AnswerGroup
End Function
Private Sub AnswerkeysT(ByVal sender As Object, ByVal e As System.EventArgs)
Answer = "True"
End Sub
Private Sub AnswerkeysF(ByVal sender As Object, ByVal e As System.EventArgs)
Answer = "False"
End Sub
Private Sub AnswerkeysD(ByVal sender As Object, ByVal e As System.EventArgs)
Answer = "Do'nt Care"
End Sub
End Class
Public Class Form1
Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
Public Sub New()
MyBase.New()
'This call is required by the Windows Form Designer.
InitializeComponent()
'Add any initialization after the InitializeComponent() call
End Sub
'Form overrides dispose to clean up the component list.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub
'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer
'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
'
'Form1
'
Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
Me.AutoScroll = True
Me.ClientSize = New System.Drawing.Size(408, 414)
Me.Name = "Form1"
Me.Text = "Form1"
End Sub
#End Region
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
LoadRadioButtons()
End Sub
Private Sub LoadRadioButtons()
Dim tempgroup As System.Windows.Forms.GroupBox
Dim Thissession(600) As QuestionsArray
Dim i As Integer
Dim topst As Integer
topst = 10
i = 1
For i = 0 To 599
Thissession(i) = New QuestionsArray(i 1, Me)
tempgroup = Thissession(i).AddNewQuestion(i 1, topst, 10)
Me.Controls.Add(tempgroup)
tempgroup.Top = topst
topst = topst 50
tempgroup.Left = 10
Next
End Sub
End ClassHave a question about something in this article? You can receive help directly from the article author. Sign up for a free trial to get started.
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