How to clear every TextBox inside a GroupBox

Question

I am having problem with emptying every TextBoxes inside a GroupBox, because my loop only clears all TextBoxes if textbox1 has value but if I try to bypass textbox1 and jump to input data to textbox2, my ClearCtrlText method doesn't work.

Please see my loop code if there's a need for change:

Public Sub ClearCtrlText(ByVal root As Control)

    For Each ctrl As Control In root.Controls
        If TypeOf ctrl Is TextBox Then ' textbox set to empty string
            If ctrl.Text <> "" Then
                ctrl.Text = Nothing
            End If
        End If
    Next
End Sub

Answer 1

I would be tempted to write this as an extension method:

Imports System.Runtime.CompilerServices

Public Module ControlExtensions

    <Extension>
    Public Sub ClearTextBoxes(source As Control)
        For Each child As Control In source.Controls
            Dim tb = TryCast(child, TextBox)

            If tb Is Nothing Then
                child.ClearTextBoxes()
            Else
                tb.Clear()
            End If
        Next
    End Sub

End Module

You can then call it on a control as though it was a member, e.g.

GroupBox1.ClearTextBoxes()

This method also includes the recursion required to access child controls inside child containers, e.g. a Panel inside the GroupBox.