Prevent NULL from being passed 1

[bvbowes]

How can I prevent a NULL from being passed in this simple cmd button so that a msgbox pops up telling the user the enter a value?

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Private Sub CmdOpenForm_Click()

Dim rs As DAO.Recordset

Set rs = Forms!frmMainEntry.RecordsetClone
rs.FindFirst "CaseNumber=" & Me!CaseNumber

DoCmd.Close

If Not rs.NoMatch Then Forms!frmMainEntry.Bookmark = rs.Bookmark

End
End Sub

 

[Remou]

[tt]If Trim(Me!CaseNumber & " ")="" Then
MsgBox "Nothing to find."
Else
'Stuff
End if[/tt]