Control Array

by Ruben 3/25/2008 12:09:00 AM

Control Array is One of the VB6 features that are no longer supported in VB.NET like automated creation of control arrays by simply copying an existing control as many times as required into an array. There is existing article in MSDN which illustrates how to create control arrays at run time, but this may not be a suitable approach in all cases.

I needed control array specially in textbox control because i'm doing data entry program with a lot of textbox, we want to simplify the coding structure of event handler like keyup, keydown, keypress, gotfocus, validation etc. With the help of open forum i found source code that easy to use and i will also share to others. Thanks to the original author of this Class ControlArray, it helps a lot for me. (see sample code below).

******* FORM ********
Option Explicit On
Imports System
Imports System.IO
Imports System.Text
Imports System.Windows.Forms

Public Class Form1
Private aTextBoxes() As TextBox
Private sFldName as String
Private sInputBox as String
Private iFldIndex as Integer

Private Sub Form1_Load(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles MyBase.Load
    'create 6 textboxes in the Form1 name properties as:
    'tbInput1
    'tbInput2
    'tbInput3
    'tbInput4
    'tbInput5
    'tbInput6
    Initialized_ArrayTextBox()
End Sub

Private Sub Initialized_ArrayTextBox()
    Dim i As Integer = 1
    aTextBoxes = ControlArray.getControlArray(Me, "tbInput")

    For i = 1 To 6
      AddHandler aTextBoxes(i).KeyPress, AddressOf tbInput_KeyPress
      AddHandler aTextBoxes(i).KeyDown, AddressOf tbInput_KeyDown
      AddHandler aTextBoxes(i).KeyUp, AddressOf tbInput_KeyUp
      AddHandler aTextBoxes(i).GotFocus, AddressOf tbInput_GotFocus
      AddHandler aTextBoxes(i).LostFocus, AddressOf tbInput_LostFocus
      AddHandler aTextBoxes(i).TextChanged, AddressOf tbInput_TextChanged
      AddHandler aTextBoxes(i).Validating, AddressOf tbInput_Validating
    Next i
End Sub

Private Sub tbInput_KeyPress(ByVal sender As Object, _
      ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles tbInput1.KeyPress
    'code here
End Sub

Private Sub tbInput_KeyDown(ByVal sender As Object, _
      ByVal e As System.Windows.Forms.KeyEventArgs) Handles tbInput1.KeyDown
    'code here
End Sub

Private Sub tbInput_GotFocus(ByVal sender As Object, _
      ByVal e As System.EventArgs) Handles tbInput1.GotFocus
      'textbox properties tag
      sFldName = sender.tag
      'textbox properties name
      sInputBox = sender.name
      'Identify the current textbox index
      iFldIndex = Microsoft.VisualBasic.Right(sInputBox, Len(sInputBox) - 7)

      aTextBoxes(iFldIndex).SelectionStart = 0
      aTextBoxes(iFldIndex).SelectionLength = Len(aTextBoxes(iFldIndex).Text)
End Sub

Private Sub tbInput_KeyUp(ByVal sender As Object, _
      ByVal e As System.Windows.Forms.KeyEventArgs) Handles tbInput1.KeyUp
    'code here
End Sub

Private Sub tbInput_LostFocus(ByVal sender As Object, _
      ByVal e As System.EventArgs) Handles tbInput1.LostFocus
    'code her
End Sub

Private Sub tbInput_TextChanged(ByVal sender As Object, _
      ByVal e As System.EventArgs) Handles tbInput1.TextChanged
    'code here
End Sub

Private Sub tbInput_Validating(ByVal sender As Object, _
      ByVal e As System.ComponentModel.CancelEventArgs) Handles tbInput1.Validating
    'code here
End Sub
End Class

*********Class Module*********
Public Class ControlArray
Public Shared Function getControlArray(ByVal frm As Windows.Forms.Form, _
       ByVal controlName As String) As System.Array
    Dim i As Short
    Dim startOfIndex As Short
    Dim alist As New ArrayList
    Dim controlType As System.Type

    Dim ctl As System.Windows.Forms.Control
    Dim strSuffix As String
    Dim maxIndex As Short = -1 'Default

    'Loop through all controls, looking for controls with the matching name pattern
    'Find the highest indexed control
    Dim allControls As ArrayList = GatherAllControls(frm)

    For Each ctl In allControls
      startOfIndex = ctl.Name.ToLower.IndexOf(controlName.ToLower)
      If startOfIndex = 0 Then
         strSuffix = ctl.Name.Substring(controlName.Length)
         If IsInteger(strSuffix) Then 'Check that the suffix is an integer (index of the array)
            If Val(strSuffix) > maxIndex Then maxIndex = Val(strSuffix) 'Find the highest indexed Element
         End If
      End If
    Next ctl

    'Add to the list of controls in correct order
    If maxIndex > -1 Then
       For i = 0 To maxIndex
          Dim aControl As Control = getControlFromName(allControls, controlName, i)
          If Not (aControl Is Nothing) Then
             controlType = aControl.GetType 'Save the object Type (uses the last control found as the Type)
          End If
          alist.Add(aControl)
       Next
    End If
    Return alist.ToArray(controlType)
End Function

Public Shared Function GatherAllControls(ByVal cntrl As Control) As ArrayList
    Dim list As New ArrayList
    If Not (TypeOf cntrl Is Form) Then
       list.Add(cntrl) 'Add the control itself (Could be a container control or the form itself!)
    End If
    If cntrl.HasChildren Then
       For Each cControl As Control In cntrl.Controls
          Dim subList As ArrayList = GatherAllControls(cControl)
          list.AddRange(subList)
       Next
    End If
    Return list
End Function

'Converts any type of like named controls on a form to a control array
'by using the notation ControlName_1, ControlName_2, where the
'can be replaced by any separator string
Public Shared Function getMixedControlArray(ByVal frm As Windows.Forms.Form, _
      ByVal controlName As String, Optional ByVal separator As String = "") As Control()
    Dim i As Short
    Dim startOfIndex As Short
    Dim alist As New ArrayList
    Dim ctl As System.Windows.Forms.Control
    Dim strSuffix As String
    Dim maxIndex As Short = -1 'Default

    'Loop through all controls, looking for controls with the matching name pattern
    'Find the highest indexed control
    Dim allControls As ArrayList = GatherAllControls(frm)

    For Each ctl In allControls
      startOfIndex = ctl.Name.ToLower.IndexOf(controlName.ToLower & separator)
      If startOfIndex = 0 Then
         strSuffix = ctl.Name.Substring(controlName.Length & separator)
         If IsInteger(strSuffix) Then 'Check that the suffix is an integer (index of the array)
            If Val(strSuffix) > maxIndex Then maxIndex = Val(strSuffix)
            'Find the highest indexed Element
         End If
      End If
    Next ctl

    'Add to the list of controls in correct order
    If maxIndex > -1 Then
       For i = 0 To maxIndex
          Dim aControl As Control = getControlFromName(allControls, controlName, i)
          alist.Add(aControl)
       Next
    End If
    Return alist.ToArray(GetType(Control))
End Function

Private Shared Function getControlFromName(ByRef frm As Windows.Forms.Form, _
       ByVal controlName As String, ByVal index As Short) As System.Windows.Forms.Control
    controlName = controlName & index
    For Each ctl As Control In frm.Controls
       If String.Compare(ctl.Name, controlName, True) = 0 Then
          Return ctl
       End If
    Next ctl
    Return Nothing
End Function

Private Shared Function getControlFromName(ByVal allControls As ArrayList, _
      ByVal controlName As String, ByVal index As Short) As System.Windows.Forms.Control
    controlName = controlName & index
    For Each ctl As Control In allControls
       If String.Compare(ctl.Name, controlName, True) = 0 Then
          Return ctl
       End If
    Next ctl
    Return Nothing
End Function

Private Shared Function IsInteger(ByVal Value As String) As Boolean
    If Value = "" Then Return False
    For Each chr As Char In Value
       If Not Char.IsDigit(chr) Then
          Return False
       End If
    Next
    Return True
End Function
End Class