' License Manager form (frmLicenseManager) Private Sub cmdValidateLicense_Click() ' Validate the license code If ValidateLicenseCode(txtLicenseCode.Text) Then MsgBox "License code is valid", vbInformation Else MsgBox "Invalid license code", vbExclamation End If End Sub

' Validate license code function Function ValidateLicenseCode(lc As String) As Boolean ' TO DO: implement license code validation logic ' ... End Function Note that this is a basic mockup, and actual implementation details may vary depending on the Kutools architecture and requirements.

You're referring to Kutools, a popular add-in for Microsoft Excel!