'______________________________________________________________

'                 C O N T R O L S   C O L L E C T I O N   D E M O

'                                          Ron Kessler

'                                      Created 9/24/08
'______________________________________________________________


'This demo shows how to cycle through the controls collection on a form to clear all testboxes.
'However, notice there is a textbox inside of a container control (Groupbox). The form's control
'collection will not see this textbox because it is inside a container control. So we will use the
'HasChildren property of the controls in the form's collection to find the nested controls!



Public Class frmMain

    Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
        '---cycle through forms collection and clear textboxes
        For Each myControl As Control In Me.Controls
            If TypeOf myControl Is TextBox Then
                myControl.Text = ""
            ElseIf myControl.HasChildren Then
                '---if it comes across a groupbox or tab control that has child controls, clear textboxes & radiobuttons in them also
                For Each nestedControl As Control In myControl.Controls
                    If TypeOf nestedControl Is TextBox Then
                        nestedControl.Text = ""
                    ElseIf TypeOf nestedControl Is RadioButton Then
                        Dim myRadioButton As RadioButton = nestedControl  'see note below
                        myRadioButton.Checked = False
                    End If
                Next

            End If
        Next

    End Sub


    'Note about the RadioButton loop above:
    'All controls have a text property (I think). But not all controls have a Checked property. So to
    'uncheck a RadioButton or Checkbox Control, I have to create a new reference variable (myRadioButton) line 31
    'and assign it to the current control being pointed to in nestedControl. Then I can access its checked
    'property and uncheck it by making it false in line 32.
End Class