How to make a validation from a checkbox and radiobutton - vb.net

Question

I'm trying to make a validation where after I click in a item from the ComboBoxwithout check any of the RadioButton it will shows de user a message. This is the piece the code that I am using to get the info from an item and fill it on DataGridView.
Private Sub cbExtensão_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cbExtensão.SelectedIndexChanged
If cbExtensão.Visible <> cbExtensão.V(rbPorData.Checked & rbPorExtensão.Checked & rbPorNome.Checked) Then
If rbPorData.Checked Then
DataGridView2.DataSource = FillDataGridViewData(cbExtensão.Text)
ElseIf rbPorExtensão.Checked Then
DataGridView2.DataSource = FillDataGridViewExtensao(cbExtensão.Text)
ElseIf rbPorNome.Checked Then
DataGridView2.DataSource = FillDataGridViewName(cbExtensão.Text)
End If
Else
MsgBox("Please, check an option to search")
End If
End Sub
What I am trying to do is making something with this line If cbExtensão.Visible <> cbExtensão.V(rbPorData.Checked & rbPorExtensão.Checked & rbPorNome.Checked) Then but I've tried a lot of things and I can«t get anything from there. Basically I want it to displays a message if user doens't select any RadioButton after click on an item from CheckBox

Answer 1

this is how I have done it for my code.
Private Sub UserMsgBox(ByVal sMsg As String)
Dim sb As New StringBuilder()
Dim oFormObject As System.Web.UI.Control
sMsg = sMsg.Replace("'", "\'")
sMsg = sMsg.Replace(Chr(34), "\" & Chr(34))
sMsg = sMsg.Replace(vbCrLf, "\n")
sMsg += "<script language=javascript "
sMsg += "type=text/" + "javascript" + ">"
smsg += "alert ('" + "Please click on a code type" + "')"
sMsg += "</" + "script" + ">"
sb = New StringBuilder()
sb.Append(sMsg)
Page.RegisterclientScriptBlock("clientScript", sMsg)
For Each oFormObject In Me.Controls
If TypeOf oFormObject Is HtmlForm Then
Exit For
End If
Next
' Add the javascript after the form object so that the
' message doesn't appear on a blank screen.
oFormObject.Controls.AddAt(oFormObject.Controls.Count, New LiteralControl(sb.ToString()))
end sub

Answer 2

As Plutonix mentionned in the comments, you can just remove the first if statement...
Private Sub cbExtensão_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cbExtensão.SelectedIndexChanged
If rbPorData.Checked Then
DataGridView2.DataSource = FillDataGridViewData(cbExtensão.Text)
ElseIf rbPorExtensão.Checked Then
DataGridView2.DataSource = FillDataGridViewExtensao(cbExtensão.Text)
ElseIf rbPorNome.Checked Then
DataGridView2.DataSource = FillDataGridViewName(cbExtensão.Text)
Else
MsgBox("Please, check an option to search")
End If
End Sub
So if no box is selected, it will fall down to the Else statement.