If nothing selected macro uses whole worksheet instead of showing error message - excel

Question

The macro offers the options to format selected text, which it does perfectly if some some cells are selected first.
However, the error handling is not working and I don't know why: if nothing is selected when I execute the macro, it formats the whole worksheet instead of showing an error message that requests a selection to be made. Any ideas why this isn't working?
Code from my UserForm ("UserForm1"):
Private Sub OKButton_Click()
Dim WorkRange As Range
Dim cell As Range
On Error Resume Next
Set WorkRange = Selection.SpecialCells _
(xlCellTypeConstants, xlCellTypeConstants)
If OptionUpper Then
For Each cell In WorkRange
cell.Value = UCase(cell.Value)
Next cell
End If
' code for the other options...
Unload UserForm1
End Sub
Code for calling the macro("Module1"):
Sub ChangeCase()
If TypeName(Selection) = "Range" Then
UserForm1.Show
Else
MsgBox "Select an area first.", vbCritical
End If
End Sub
I'm using MS Excel 2010. (Hope I didn't forget any relevant information.)

Answer 1

You could alter the userform code to something like:
Private Sub OKButton_Click()
Dim WorkRange As Range
Dim cell As Range
' If Selection.Cells.Count > 1 then (I corrected this to the line below, then it worked!
If Selection.Cells.Count = 1 then
If Msgbox("Only one cell selected - do you want to format the whole sheet?", vbyesno) = vbNo then Exit Sub
End If
On Error Resume Next
Set WorkRange = Selection.SpecialCells _
(xlCellTypeConstants, xlCellTypeConstants)
If OptionUpper Then
For Each cell In WorkRange
cell.Value = UCase(cell.Value)
Next cell
End If
' code for the other options...
Unload Me
End Sub

Answer 2

A Much Better Solution to If nothing is selected.
Public Sub IfNoSelection()
Application.ScreenUpdating = False
'Activate your Sheet
Sheets("Name Of Sheet Here").Select
'Select your range without selecting the header (column D)
Range(Cells(2, 4), Cells(Rows.Count, 4)).Select
'This Line Checks if what is selected is selected.
If WorksheetFunction.CountA(Selection) = 0 Then
Else
'enter code here
End If
Application.ScreenUpdating = True
End Sub