I have a strange problem with the combobox and the controlsource property. Becouse of a select-sql command that has to include THISFORM I have to set the rowsource from init event. The code in the init event looks like this:

THIS.ROWSOURCE = "SELECT ALLTRIM(efternamn) +', '+ ALLTRIM(fornamn), person.idnr " + ;
"FROM mds!person, mds!foretag, mds!connect INTO CURSOR tKlientPerson " + ;
"WHERE foretag.idnr = THISFORM.oForetag.GetIdnr() AND foretag.idnr = connect.idnr_1 " + ;
"AND connect.idnr_2 = person.idnr ORDER BY 1"

THIS.REQUERY()
THIS.CONTROLSOURCE = 'THISFORM.oKlient.df_person' && ERROR
DODEFAULT()

When I do THIS.CONTROLSOURCE = ... I get the following error:
1881 - Error with cboPerson - Value : Data type mismatch.

Why? The control shows the right information so there is nothing wrong with the select-sql command. But I can't set the controlsource without having this problem. How can I solve this?