General :: How To Undo Delete Command In Datasheet View

When I had a subform (continous form) I had a code which check, that record was used in other form, if yes, then code not allowed to delete this record, if not, record was deleted. But now I have a datasheet form, and the question is, What should I do, to have the same results what I had in continous form.

Now it doesn't matter that I past this code in "Before Del Confirm", "On delete", "After Del Confirm", this code doesn't work in this view of form. Always if I click (right button) on record, then i choose "delete record" MS Access delete my record without checking that was used in other form or not.

Code:
If Not IsNull(DLookup("Id_Gora_Zlecenia.Value", "TblDolZlecenia", "Id_Gora_Zlecenia.Value=" & ID_gora_zlecenia)) Then
MsgBox "You can't delete this record because it is used in another form"
Exit Sub
End If
DeleteRecord Me
End Sub

DeleteRecord:

Code:
Public Function DeleteRecord(ByRef f As Form) As Boolean
DeleteRecord = False
On Error Resume Next
DoCmd.SetWarnings False
If Not f.NewRecord Then
DoCmd.RunCommand acCmdDeleteRecord

[Code] .....